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\vspace{\abovedisplayskip}
\noindent
\LR{A} \LR{B} \LR{C} \LR{D} \LR{E} \LR{F} \LR{G} \LR{H} \LR{I} \LR{J}
\LR{K} \LR{L} \LR{M} \LR{N} \LR{O} \LR{P}
\LR{R} \LR{S} \LR{T} \LR{U} \LR{V} \LR{W} \LR{X} \LR{Y}
\\

\Letter{A}%
\macrodef{above\_}{above_}{}
  {gen}
  {string position above relative to current direction}
\macrodef{abs\_}{abs_}{({\sl number})}
  {gen}
  {absolute value function}
\macrodef{ACsymbol}{ACsymbol}{(at {\sl position, len, ht,}
  [n:][A]U|D|L|R|{\sl degrees}) }
  {cct}
  {draw a stack of $n$ (default 1) AC symbols
   ( 1-cycle sine waves); If arg 4 contains A, two arcs
   are used.  The current drawing direction is default, otherwise Up, Down,
   Left, Right, or at {\sl degrees} slant; \seesect{Twoterminal:} e.g.,\\ 
   {\tt ebox; $\lbrace$ACsymbol(at last [],{,}dimen\_/8)$\rbrace$}}
\macrodef{adc}{adc}{({\sl width,height,nIn,nN,nOut,nS})}
  {cct}
  {ADC with defined width, height, and number of inputs {\tt In$i$},
    top terminals {\tt N$i$}, ouputs {\tt Out$i$},
    and bottom terminals~{\tt S$i$}}
\macrodef{addtaps}{addtaps}{[{\sl arrowhd}
  | type={\sl arrowhd};name={\sl Name}],
    {\sl fraction, length, fraction, length,} $\cdots$)}
  {cct}
  {Add taps to the previous two-terminal element.
   {\sl arrowhd} = blank or one of {\tt . - <- -> <->}.
   Each fraction determines the position along the element body of the tap.
   A negative length draws the tap to the right of the current
   direction; positive length to the left.
   Tap names are Tap1, Tap2, $\cdots$ by default  or
   Name1, Name2, $\cdots$ if specified 
   \seesect{Composite:}}
\macrodef{along\_}{along_}{({\sl linear object name})}
  {gen}
  {short for {\tt between {\sl name}.start and {\sl name}.end}}
\macrodef{Along\_}{Along_}{({\sl LinearObj,distance,}[R])}
  {gen}
  {Position arg2 (default all the way) along a linear object
   from {\tt .start} to {\tt .end}
   (from {\tt .end} to {\tt .start} if arg3={\tt R}) }
\macrodef{amp}{amp}{(\linespec,{\sl size})}
  {cct}
  {amplifier\seesect{Twoterminal:}}
\macrodef{And, Or, Not, Nand, Nor, Xor, Nxor, Buffer}%
 {And, Or, Not, Nand, Nor, Xor, Nxor, Buffer}{}
  {log}
  {Wrappers of {\tt AND\_gate}, $\ldots$ for use in the {\tt Autologix}
   macro}
\macrodef{AND\_gate}{AND_gate}{({\sl n},N)}
  {log}
  {basic `and' gate, 2 or {\sl n\/} inputs; {\tt N}=negated input.
   Otherwise, arg1 can be a sequence of letters {\tt P|N}
   to define normal or negated inputs
    \seesect{Logicgates:}}
\macrodef{AND\_gen}{AND_gen}{($n$,{\sl chars},[{\sl wid},[{\sl ht}]])}
  {log}
  {general AND gate: $n$=number of inputs $(0\leq n\leq 16)$;
           {\sl chars:}
           B=base and straight sides; A=Arc;
           [N]NE,[N]SE,[N]I,[N]N,[N]S=inputs or circles;
           [N]O=output; C=center.
   Otherwise, arg1 can be a sequence of letters {\tt P|N}
   to define normal or negated inputs.}
\macrodef{AND\_ht}{AND_ht}{}
  {log}
  {height of basic `and' and `or' gates in {\tt L\_unit}s}
\macrodef{AND\_wd}{AND_wd}{}
  {log}
  {width of basic `and' and `or' gates in {\tt L\_unit}s}
\macrodef{antenna}{antenna}{%
  (at {\sl location}, T, A|L|T|S|D|P|F, U|D|L|R|{\sl degrees})}
  {cct}
  {antenna, without stem for nonblank 2nd arg; {\tt A}=aerial,
    {\tt L}=loop, {\tt T}=triangle, {\tt S}=diamond, {\tt D}=dipole,
    {\tt P}=phased, {\tt F}=fork;
    up, down, left, right, or angle from horizontal (default 90) 
   \seesect{Composite:}}
\macrodef{arca}{arca}{({\sl absolute chord linespec}, ccw|cw, {\sl radius},
   {\sl modifiers}) }
  {gen}
  {arc with acute angle (obtuse if radius is negative), drawn in a [ ] block}
\macrodef{ArcAngle}{ArcAngle}{({\sl position, position, position, radius,
  modifiers, label}) }
  {gen}
  {Arc angle symbol drawn ccw at arg2. Arg4 is the radius from arg2;
     arg5 contains line attributes, e.g., {\tt thick linethick/2 ->};
     arg6 is an optional label at mid-arc}
\macrodef{arcd}{arcd}{({\sl center},
  {\sl radius},{\sl start degrees},{\sl end degrees}) }
  {gen}
  {Arc definition (see {\tt arcr}), angles in degrees
    \seesect{Positions:}}
\macrodef{arcdimension\_}{arcdimension_}{({\sl arcspec},{\sl offset},%
{\sl label},
    D|H|W|{\sl blank width},{\sl tic offset},{\sl arrowhead })}
  {gen}
  {like {\tt dimension\_}, for drawing arcs for dimensioning diagrams;
      {\sl arrowhead=}{\tt -> | <-}. Uses the first argument as the attributes
      of an invisible arc: {\tt arc invis }{\sl arg1}.  {\sl Arg2} is the
      radial displacement (possibly negative) of the dimension arrows.
      If {\sl arg3} is {\tt s\_box(\ldots)} or {\sl rs\_box(\ldots)} and
      {\sl arg4=}{\tt D|H|W} then {\sl arg4} means:
      {\tt D:} blank width is the diagonal length of {\sl arg3};
      {\tt H:} blank width is the height of {\sl arg3} + {\tt textoffset*2};
      {\tt W:} blank width is the width of {\sl arg3} + {\tt textoffset*2};
      otherwise {\sl arg4} is the absolute blank width}
\macrodef{arcr}{arcr}{({\sl center},{\sl radius},{\sl start angle},{\sl
    end angle,modifiers,ht}) }
  {gen}
  {Arc definition.  If arg5 contains {\tt <-} or {\tt ->} then a midpoint
    arrowhead of height equal to arg6 is added. Arg5 can contain modifiers
    (e.g. outlined "red"), for the arc and arrowhead.  Modifiers following
    the macro affect the arc only,
    e.g., {\tt arcr(A,r,0,pi\_/2,->) dotted ->}
   \seesect{Positions:}}
\macrodef{arcto}{arcto}{({\sl position 1},{\sl position 2},{\sl
    radius},[dashed|dotted])}
  {gen}
  {line toward position 1 with rounded corner toward position 2}
\macrodef{arrester}{arrester}{(\linespec,{\sl chars},
                                   {\sl len}[:arrowhead ht],
                                   {\sl ht}[:arrowhead wid] )}
  {cct}
{
                                 {\sl Arg2 chars:}
                                   {\tt G=} spark gap (default),
                                   {\tt g=} general (dots),
                                   {\tt E=} gas discharge,
                                   {\tt S=} box enclosure,
                                   {\tt C=} carbon block,
                                   {\tt A=} electrolytic cell,
                                   {\tt H=} horn gap,
                                   {\tt P=} protective gap,
                                   {\tt s=} sphere gap,
                                   {\tt F=} film element,
                                   {\tt M=} multigap.
                                 {\sl Modifiers in arg2:}
                                   {\tt R=} right orientation,
                                   {\tt L=} left orientation,
                                   {\tt D=} 3-terminal element for {\tt S, E}
                                      only, with terminals {\sl A, B, G}
   \seesect{Twoterminal:}}
\macrodef{arrowline}{arrowline}{(\linespec)}
  {cct}
  {line (dotted, dashed permissible) with centred arrowhead
    \seesect{Twoterminal:}}
\macrodef{AutoGate}{AutoGate}{}
  {log}
  {Draw the tree for a gate as in the {\tt Autologix} macro.  No inputs
   or external connections are drawn.  The names of the internal gate
   inputs are stacked in {\tt `AutoInNames'}}
\macrodef{assign3}{assign3}{({\sl var name,var name,var name,arg4,arg5,arg6})}
  {gen}
  {Assigns \$1 = arg4 if \$1 is nonblank; similarly \$2 = arg5 and \$3 = arg6}
\macrodef{Autologix}{Autologix}%
 {({\sl Boolean function sequence},%
    [N[oconnect]][L[eftinputs]][R][V][M][;offset={\sl value}])}
  {log}
  {Draw the Boolean expressions defined in function notation.
   The first argument is a semicolon (;)-separated sequence of
   Boolean function specifications using the functions
   {\tt And, Or, Not, Buffer, Xor, Nand, Nor, Nxor}
   with variables, e.g.,
   {\tt Autologix(And(Or(x1,~x2),Or(~x1,x2)));}.
   Each function specification is of the form
   {\tt {\sl function}({\sl arguments}) [@{\sl attributes}]}.
   \par
   Function outputs are aligned vertically but appending
   {\tt@}{\sl attributes} to a function can be used to place it.
   \par
   The function arguments are variable names or nested Boolean functions.
   Each unique variable {\sl var} causes an input point {\tt In}{\sl var} 
   to be defined.  Preceding the variable by a {\tt \~{}} causes a NOT gate
   to be drawn at the input.
   The inputs are drawn in a row at the upper left by default.
   An {\tt L} in arg2 draws the inputs in a column at the left;
   {\tt R} reverses the order of the drawn inputs;
   {\tt V} scans the expression from right to left
   when listing inputs;
   {\tt M} draws the left-right mirror image of the diagram;
   and {\tt N} draws only the function tree without the input array.
   The inputs are labelled {\tt In1}, {In2}, \ldots and the function
   outputs are {\tt Out1}, {Out2}, \dots.
   Each variable {\sl var} corresponds also to one of the input array
   points with label {\tt In}{\sl var}.
   Setting {\tt offset=}{\sl value} displaces the
   drawn input list in order to disambiguate the input connections when {\tt L}
   is used.
   \par
   In the (possibly rare) case where one or more inputs of a normal function
   gate is to have a NOT-circle, an additional first argument of the function
   is inserted, of the form {\tt [{\sl charseq}]}, where {\sl charseq}
   is a string containing the characters {\tt P} for a normal input or
   {\tt N} for a negated input, the length of the string equal to the number
   of gate inputs.  For example:
   {\tt Autologix(Xor([PN],And(x,y),And(x,y)),LRV)}}

\Letter{B}%
\macrodef{b\_}{b_}{}
  {gen}
  {blue color value}
\macrodef{b\_current}{b_current}{({\sl label},{\sl pos},In|Out,Start|End,{\sl
    frac})}
  {cct}
  {labelled branch-current arrow to {\sl frac} between branch end and body
    \seesect{Branchcurrent:}}
\macrodef{basename\_}{basename_}{({\sl string sequence, separator})}
  {gen}
  {Extract the rightmost name from a sequence of names separated by arg2
   (default dot ``.'')}
\macrodef{battery}{battery}{(\linespec,{\sl n},R)}
  {cct}
  {n-cell battery: default 1 cell,
  R=reversed polarity\seesect{Twoterminal:}}
\macrodef{beginshade}{beginshade}{({\sl gray value})}
  {gen}
  {begin gray shading, see {\tt shade}
   e.g., {\tt beginshade(.5);} {\sl closed line specs}; {\tt endshade}}
\macrodef{bell}{bell}{( U|D|L|R|{\sl degrees}, {\sl size})}
  {cct}
  {bell, {\sl In1} to {\sl In3} defined
   \seesect{Composite:}}
\macrodef{below\_}{below_}{}
  {gen}
  {string position relative to current direction}
\macrodef{Between\_}{Between_}{({\sl Pos1, Pos2,distance,}[R])}
  {gen}
  {Position {\sl distance} from {\sl Pos1} toward {\sl Pos2}.  If
   the fourth arg is {\tt R} then from {\sl Pos2} toward {\sl Pos1}.}
\macrodef{bi\_tr}{bi_tr}{(\linespec,L|R,P,E)}
  {cct}
  {left or right, N- or P-type bipolar transistor, without or with envelope 
    \seesect{Semiconductors:}}
\macrodef{bi\_trans}{bi_trans}{(\linespec,L|R,{\sl chars},E)}
  {cct}
  { bipolar transistor, core left or right; chars:
   {\tt BU}=bulk line,
   {\tt B}=base line and label,
   {\tt S}=Schottky base hooks,
   {\tt uEn|dEn}=emitters E0 to En,
   {\tt uE|dE}=single emitter,
   {\tt Cn|uCn|dCn}=collectors C0 to Cn; {\tt u} or {\tt d} add an arrow,
   {\tt C}=single collector; {\tt u} or {\tt d} add an arrow,
   {\tt G}=gate line and location,
   {\tt H}=gate line; {\tt L}=L-gate line and location,
   {\tt [d]D}=named parallel diode,
   {\tt d}=dotted connection,
   {\tt [u]T}=thyristor trigger line;
   arg 4 = E: envelope
    \seesect{Semiconductors:}}
\macrodef{binary\_}{binary_}{($n$, [$m$])}
  {gen}
  {binary representation of $n,$ left padded to $m$ digits if the second
   argument is nonblank}
\macrodef{BOX\_gate}{BOX_gate}{({\sl inputs,output,swid,sht,label})}
  {log}
  {output=[{\tt P|N}], inputs=[{\tt P|N}]$\ldots$, sizes swid and sht
  in {\tt L\_unit}s (default {\tt AND\_wd} = 7)
    \seesect{Logicgates:}}
\macrodef{boxcoord}{boxcoord}{({\sl planar obj},{\sl x fraction},{\sl y
    fraction})}
  {gen}
  {internal point in a planar object}
\macrodef{boxdim}{boxdim}{({\sl name},h|w|d|v,{\sl default})}
  {gen}
  {evaluate, e.g.\ {\sl name}{\tt \_w} if defined, else {\sl default\/}
   if given, else 0 {\tt v} gives sum of {\tt d} and {\tt h} values
     \seesect{Interaction:}}
\macrodef{bp\_\_}{bp__}{}
  {gen}
  {big-point-size factor, in scaled inches, ({\tt *scale/72})}
\macrodef{bswitch}{bswitch}{(\linespec, [L|R],chars)}
  {cct}
  {pushbutton switch R=right orientation (default L=left);
     chars: O= normally open, C=normally closed }
\macrodef{BUF\_ht}{BUF_ht}{}
  {log}
  {basic buffer gate height in {\tt L\_unit}s}
\macrodef{BUF\_wd}{BUF_wd}{}
  {log}
  {basic buffer gate width in {\tt L\_unit}s}
\macrodef{BUFFER\_gate}{BUFFER_gate}{(\linespec, [N|B],
  {\sl wid, ht,} [N|P]\char42, [N|P]\char42, [N|P]\char42)}
  {log}
  {basic buffer, dfault 1 input or as a 2-terminal element,
    arg2: {\tt N}=negated input, {\tt B}=box gate; arg 5:
    normal ({\tt P}) or negated {\tt N}) inputs labeled In1 
    \seesect{Logicgates:}}
\macrodef{BUFFER\_gen}{BUFFER_gen}{({\sl chars,wd,ht},[N|P]*,[N|P]*,[N|P]*)}
  {log}
  {general buffer, {\sl chars:} {\tt T}=triangle,
            {\tt [N]O}=output location {\tt Out}
            ({\tt NO} draws circle {\tt N\_Out});
            {\tt [N]I, [N]N, [N]S, [N]NE, [N]SE}
            input locations; {\tt C}=centre location.
            Args 4-6 allow alternative
            definitions of respective {\tt In, NE,}
            and {\tt SE} argument sequences }
\macrodef{buzzer}{buzzer}{( U|D|L|R|{\sl degrees, size,}[C])}
  {cct}
  {buzzer, {\sl In1} to {\sl In3} defined, C=curved
   \seesect{Composite:}}
\Letter{C}%
\macrodef{c\_fet}{c_fet}{(\linespec,R,P)}
  {cct}
  {left or right, plain or negated pin simplified MOSFET}
\macrodef{capacitor}{capacitor}{(\linespec,{\sl chars},R,
    {\sl height}, {\sl wid})}
  {cct}
  {capacitor, {\sl chars}:
    F or blank=flat plate;
    dF flat plate with hatched fill;
    C=curved-plate;
    dC=curved-plate with variability arrowhead;
    CP=constant phase element;
    E=polarized boxed plates;
    K=filled boxed plates;
    M=unfilled boxes;
    M=one rectangular plate;
    P=alternate polarized;
    + adds a polarity sign;
    +L polarity sign to the left of drawing direction;
    arg3:  R=reversed polarity;
    arg4 = height (defaults F: {\tt dimen\_}$/3$,
      C,P: {\tt dimen\_}$/4$, E,K: {\tt dimen\_}$/5$);
    arg5 = wid (defaults F: {\sl height}*0.3,
      C,P: {\sl height}*0.4, CP: {\sl height}*0.8, E,K: {\sl height})
    \seesect{Twoterminal:}}
\macrodef{cbreaker}{cbreaker}{(\linespec, L|R, D|Th|TS, body name)}
  {cct}
  {circuit breaker to left or right, {\tt D}=with dots; {\tt Th}=thermal;
   {\tt TS}=squared thermal; default body bounding box name is
     {\sl Br}\seesect{Twoterminal:}}
\macrodef{ccoax}{ccoax}{(at {\sl location}, M|F, {\sl diameter})}
  {cct}
  {coax connector, {\tt M}=male, {\tt F}=female
    \seesect{Composite:}}
\macrodef{cct\_init}{cct_init}{}
  {cct}
  {initialize circuit-diagram environment (reads {\tt libcct.m4})}
\macrodef{centerline\_}{centerline_}{({\sl linespec, thickness{\tt|}color,
   minimum long dash len, short dash len, gap len}}
  {gen}
  {Technical drawing centerline}
\macrodef{Cintersect}{Cintersect}{({\sl Pos1, Pos2, rad1, rad2,} [R])}
  {gen}
  {Upper (lower if arg5={\tt R}) intersection of circles at
    {\sl Pos1} and {\sl Pos2}, radius {\sl rad1} and {\sl rad2}}
\macrodef{clabel}{clabel}{({\sl label},{\sl label},{\sl label},[{\sl arg4}],%
    [{\sl block name}])}
  {cct}
  {Triple label along the drawing axis of the body of an element in the
    current direction \seesect{Labels:}.  Labels are placed at the
    beginning, centre, and end of the last {\tt []} block (or a named
    {\tt []} block). Each label is treated as math by default, but is
    copied literally if it is in double quotes or sprintf.
    {\sl Arg4} can be {\tt above,} {\tt below,} {\tt left,} or {\tt
    right} to supplement the default relative position.  The fifth
    argument is the optional name of the {\tt []} block to be labelled,
    which is {\tt last []} by default.}
\macrodef{cm\_\_}{cm__}{}
  {gen}
  {absolute centimetres}
\macrodef{consource}{consource}{(\linespec,V|I|v|i,R)}
  {cct}
  {voltage or current controlled source with alternate forms;
   {\tt R}=reversed polarity\seesect{Twoterminal:}}
\macrodef{contact}{contact}{({\sl chars})}
  {cct}
  {single-pole contact:
   {\tt O}= normally open,
   {\tt C}= normally closed (default),
   {\tt I}= open circle contacts,
   {\tt P}= three position,
   {\tt R}= right orientation,
   {\tt T}= T contacts,
   {\tt U}= U contacts
   \seesect{Composite:}}
\macrodef{contacts}{contacts}{({\sl count, chars})}
  {cct}
  {multiple ganged single-pole contacts:
   {\tt P}= three position,
   {\tt O}= normally open,
   {\tt C}= normally closed,
   {\tt D}= dashed ganging line over contact armatures
   {\tt I}= open circle contacts,
   {\tt R}= right orientation,
   {\tt T}= T contacts,
   {\tt U}= U contact lines parallel to drawing direction
   \seesect{Composite:}}
\macrodef{contline}{contline}{({\sl line})}
  {gen}
  {evaluates to {\tt continue}
    if processor is {\bf dpic}, otherwise to first arg (default {\tt line})}
\macrodef{corner}{corner}{({\sl line thickness,attributes,turn radians})}
  {gen}
  { Mitre (default filled square) drawn at end of last line or at a
    given position.
    arg1 default: current line thickness;
    arg2: e.g. {\tt outlined} {\sl string}; if arg2 starts with
    {\tt at} {\sl position} then a manhattan (right-left-up-down) corner
    is drawn;
    arg3= radians (turn angle, +ve is ccw, default $\pi/2$).
    The corner is enclosed in braces
    in order to leave {\tt Here} unchanged unless arg2 begins with {\tt at}
    \seesect{Corners:}}
\macrodef{Cos}{Cos}{({\sl integer})}
  {gen}
  {cosine function, {\sl integer\/} degrees}
\macrodef{cosd}{cosd}{({\sl arg})}
  {gen}
  {cosine of an expression in degrees}
\macrodef{Cosine}{Cosine}{( {\sl amplitude}, {\sl freq}, {\sl time},
    {\sl phase} )}
  {gen}
  {function $a\times\cos(\omega t + \phi)$ }
\macrodef{cross}{cross}{(at {\sl location, size}|{\sl keys})}
  {gen}
  {Plots a small cross.  The possible key-value pairs are:
    {\tt size={\sl expr};},
    {\tt line={\sl attributes};} }
\macrodef{cross3D}{cross3D}{({\sl x1,y1,z1,x2,y2,z2})}
  {3D}
  {cross product of two triples}
\macrodef{crossover}{crossover}{(\linespec, [L|R][:{\sl line attributes}],
  Line1, Line2, .{.}.)}
  {cct}
  {line jumping left or right over ordered named lines\seesect{Semiconductors:}}
\macrodef{crosswd\_}{crosswd_}{}
  {gen}
  {cross dimension}
\macrodef{csdim\_}{csdim_}{}
  {cct}
  {controlled-source width}
\Letter{D}%
\macrodef{d\_fet}{d_fet}{(\linespec,R,P,E|S)}
  {cct}
  {left or right, N or P depletion MOSFET, envelope or simplified
    \seesect{Semiconductors:}}
\macrodef{dabove}{dabove}{(at {\sl location})}
  {darrow}
  {above (displaced dlinewid/2)}
\macrodef{dac}{dac}{({\sl width,height,nIn,nN,nOut,nS})}
  {cct}
  {DAC with defined width, height, and number of inputs {\tt In$i$},
    top terminals {\tt N$i$}, ouputs {\tt Out$i$},
    and bottom terminals~{\tt S$i$} \seesect{Logicgates:}}
\macrodef{darc}{darc}{({\sl center position},
  {\sl radius}, {\sl start radians}, {\sl end radians}, {\sl dline thickness},
  {\sl arrowhead wid}, {\sl arrowhead ht},
  {\sl terminals})}
  {darrow}
  {See also {\tt Darc}.
   CCW arc in {\tt dline} style, with closed ends or (dpic only) arrowheads.
  Permissible {\sl terminals}:
  {\sl x}{\tt -},
  {\tt -}{\sl x}, {\sl x}{\tt -}{\sl x}, {\tt ->}, {\sl x}{\tt ->},
  {\tt <-}, {\tt <-}{\sl x}, {\tt <->}
  where {\sl x} means {\tt |} or (half-thickness line) {\tt !}.}
\macrodef{Darc}{Darc}{({\sl center position},
  {\sl radius}, {\sl start radians}, {\sl end radians},
  {\sl parameters})}
  {darrow}
  {Wrapper for {\tt darc}.
   CCW arc in {\tt dline} style, with closed ends or (dpic only) arrowheads.
  Semicolon-separated {\sl parameters}:
  {\tt thick=}{\sl value}, {\tt wid=}{\sl value}, {\tt ends=}
  {\sl x}{\tt -},
  {\tt -}{\sl x}, {\sl x}{\tt -}{\sl x}, {\tt ->}, {\sl x}{\tt ->},
  {\tt <-}, {\tt <-}{\sl x}, {\tt <->}
  where {\sl x} means {\tt |} or (half-thickness line) {\tt !}.}
\macrodef{Darlington}{Darlington}{(L|R,{\sl chars})}
  {cct}
  {Composite Darlington pair Q1 and Q2 with internal locations E, B, C;
   Characters in {\sl arg2:}
   E= envelope,
   P= P-type,
   B1= internal base lead,
   D= damper diode,
   R1= Q1 bias resistor; E1= ebox,
   R2= Q2 bias resistor; E1= ebox,
   Z= zener bias diode 
    \seesect{Semiconductors:}}
\macrodef{darrow\_init}{darrow_init}{}
  {darrow}
  {initialize darrow drawing parameters (reads {\tt darrow.m4})}
\macrodef{Darrow}{Darrow}{(\linespec, {\sl parameters})}
  {darrow}
  {Wrapper for {\tt darrow}.
  Semicolon-separated {\sl parameters}:
    {\tt S}, {\tt E} truncate at start or end by dline thickness/2;
    {\tt thick=}{\sl val}   (total thicknes, ie width);
    {\tt wid=}{\sl val}     (arrowhead width);
    {\tt ht=}{\sl val}      (arrowhead height);
    {\tt ends=}
      {\sl x}{\tt -}{\sl x} or
      {\tt -}{\sl x} or
      {\sl x}{\tt -} where {\sl x} is {\tt !} (half-width line)
       or {\tt |} (full-width line).}
\macrodef{darrow}{darrow}{(\linespec,
  t,t,{\sl width},{\sl arrowhd wd},{\sl arrowhd ht},{\sl parameters})}
  {darrow}
  {See also {\tt Darrow}.
   double arrow, truncated at beginning or end, specified sizes,
    with arrowhead or closed stem.
    {\sl parameters=}
    {\tt {\sl x}-} or {\tt ->} or {\tt {\sl x}->} or {\tt <-} or {\tt <-{\sl x}}
    or {\tt <->} where {\sl x} is {\tt |} or {\tt !}.
    The {\tt !-} or {\tt -!} parameters close
    the stem with half-thickness lines to simplify butting to other objects. }
\macrodef{dashline}{dashline}{(\linespec,{\sl thickness}|{\sl color}|<->,
                                  {\sl dash len, gap len},G)}
  {gen}
  {dashed line with dash at end ({\tt G} ends with gap)}
\macrodef{dbelow}{dbelow}{(at {\sl location})}
  {darrow}
  {below (displaced dlinewid/2)}
\macrodef{dcosine3D}{dcosine3D}{({\sl i,x,y,z})}
  {3D}
  {extract i-th entry of triple x,y,z}
\macrodef{DCsymbol}{DCsymbol}{(at {\sl position, len, ht,}
  U|D|L|R|{\sl degrees}) }
  {cct}
  {A DC symbol (a dashed line below a solid line).
   The current drawing direction is default, otherwise Up, Down,
   Left, Right, or at {\sl degrees} slant; e.g., 
   {\tt source(up\_ dimen\_); $\lbrace$ DCsymbol(at last [],,,R) $\rbrace$}
   \seesect{Twoterminal:} }
\macrodef{delay\_rad\_}{delay_rad_}{}
  {cct}
  {delay radius}
\macrodef{delay}{delay}{(\linespec,{\sl size})}
  {cct}
  {delay element\seesect{Twoterminal:}}
\macrodef{deleminit\_}{deleminit_}{}
  {darrow}
  {sets drawing direction for dlines}
\macrodef{Deltasymbol}{Deltasymbol}{(at {\sl position},keys,
    U|D|L|R|{\sl degrees}) (default {\tt U} for up)}
  {cct}
  {Delta symbol for power-system diagrams.
   {\sl keys:} {\tt size={\sl expression;}}
    {\tt type=C|O} (default {\tt C} for closed;
      {\tt O} draws an ``open'' symbol); }
\macrodef{Demux}{Demux}{({\sl n},{\sl label},
  {\tt [L][B|H|X][N[{\sl n}]|S[{\sl n}]][[N]OE],
   {\sl wid},{\sl ht}})}
  {log}
  {binary multiplexer, $n$ inputs,
    {\tt L} reverses input pin numbers,
    {\tt B} displays binary pin numbers,
    {\tt H} displays hexadecimal pin numbers,
    {\tt X} do not print pin numbers,
    {\tt N[{\sl n}]} puts Sel or Sel$0$ .. Sel$n$ at the top
    (i.e., to the left of the drawing direction),
    {\tt S[{\sl n}]} puts the Sel inputs at the bottom (default)
    {\tt OE} ({\tt N=}negated) {\tt OE} pin
    \seesect{Logicgates:}}
\macrodef{dend}{dend}{(at {\sl location})}
  {darrow}
  {close (or start) double line}
\macrodef{dfillcolor}{dfillcolor}{}
  {darrow}
  {dline fill color (default white)}
\macrodef{diff\_}{diff_}{({\sl a},{\sl b})}
  {gen}
  {difference function}
\macrodef{diff3D}{diff3D}{({\sl x1,y1,z1,x2,y2,z2})}
  {3D}
  {difference of two triples}
\macrodef{dimen\_}{dimen_}{}
  {cct}
  {size parameter for scaling circuit element bodies \seesect{Circuitscaling:}}
\macrodef{dimension\_}{dimension_}{(\linespec,{\sl offset},{\sl label},
    D|H|W|{\sl blank width},{\sl tic offset},{\sl arrowhead })}
  {gen}
  {macro for dimensioning diagrams;
      {\sl arrowhead=}{\tt -> | <-}}
\macrodef{diode}{diode}{(\linespec,%
B|b|CR|D|G|L|LE[R]|P[R]|S|Sh|T|U|V|v|w|Z|chars,%
[R][E])}
  {cct}
  {diode:
   {\tt B}=bi-directional,
   {\tt b}=bi-directional with outlined zener crossbar,
   {\tt CR}=current regulator,
   {\tt D}=diac,
   {\tt G}=Gunn,
   {\tt L}=open form with centre line,
   {\tt LE[R]}=LED [right],
   {\tt P[R]}=photodiode [right],
   {\tt S}=Schottky,
   {\tt Sh}=Shockley,
   {\tt T}=tunnel,
   {\tt U}=limiting,
   {\tt V}=varicap,
   {\tt v}=varicap (curved plate),
   {\tt w}=varicap (reversed polarity),
   {\tt Z}=zener;
   appending {\tt K} to arg 2 draws open arrowheads;
   arg 3: {\tt R}=reversed polarity, {\tt E}=enclosure \seesect{Twoterminal:}}
%\macrodef{DIP}{DIP}{({\sl pin count, attributes})}%
%  {log}
%  {Dual in-line package diagram. Default pin count = 8.
%   Arg2 ({\sl attributes})= semicolon-separated list of optional terms:
%   {\tt bodywid=}{\sl expr} (default 0.25$\,$in${}={}$5{\tt *L\_unit}),
%   {\tt bodylen=}{\sl expr} (default {\sl pin count} $\times$ {\sl pin pitch}),
%   {\tt pinpitch=}{\sl expr} (default 0.1),
%   {\tt pinwid=}{\sl expr} (default 0.06),
%   {\tt pinlen=}{\sl expr} (default 0.05),
%   {\tt direct=U|D|L|R} (default {\tt U} for up),
%   {\tt type=I|Q} (default {\tt I}; Q=pins of alternating length)
%   \seesect{Logicgates:}}
\macrodef{dir\_}{dir_}{}
  {darrow}
  {used for temporary storage of direction by darrow macros}
\macrodef{distance}{distance_}{({\sl Position 1}, {\sl Position2})}
  {gen}
  {distance between named positions}
\macrodef{distance}{distance}{({\sl position}, {\sl position})}
  {gen}
  {distance between positions}
\macrodef{dlabel}{dlabel}{({\sl long},{\sl lat},{\sl label},{\sl
     label},{\sl label},{\sl chars})}
  {cct}
  {general triple label; {\sl chars:}
    $x$ (drawing direction) displacement is from the centre of the last
      line rather than the centre of the last {\tt [ ]};
    L,R,A,B align labels ljust, rjust, above,
      or below (absolute) respectively  \seesect{Labels:}}
\macrodef{dleft}{dleft}{}
  {darrow}
  {double line left turn}
\macrodef{Dline}{Dline}{(\linespec, {\sl parameters})}
  {darrow}
  {Wrapper for {\tt dline}.
  Semicolon-separated {\sl parameters}:
    {\tt S}, {\tt E} truncate at start or end by dline thickness/2;
    {\tt thick=}{\sl val}   (total thicknes, ie width);
    {\tt ends=}
      {\sl x}{\tt -}{\sl x} or
      {\tt -}{\sl x} or
      {\sl x}{\tt -} where {\sl x} is {\tt !} (half-width line)
       or {\tt |} (full-width line).}
\macrodef{dline}{dline}{(\linespec,t,t,{\sl width},{\sl parameters})}
  {darrow}
  {See also {\tt Dline}.
   Double line, truncated by half width at either end, closed
    at either or both ends.
   {\sl parameters=}
      {\sl x}{\tt -}{\sl x} or
      {\tt -}{\sl x} or
      {\sl x}{\tt -} where {\sl x} is {\tt !} (half-width line)
       or {\tt |} (full-width line).}
\macrodef{dlinewid}{dlinewid}{}
  {darrow}
  {width of double lines}
\macrodef{dljust}{dljust}{(at {\sl location})}
  {darrow}
  {ljust (displaced dlinewid/2)}
\macrodef{dn\_}{dnx}{}
  {gen}
  {down with respect to current direction}
\macrodef{dna\_}{dna_}{}
  {cct}
  {internal character sequence that specifies which subcomponents are drawn}
%\macrodef{dnm\_}{dnm_}{}
%  {cct}
%  {similar to dna\_}
\macrodef{dot}{dot}{(at {\sl location},{\sl radius}|{\sl keys},{\sl fill})}
  {gen}
  {Filled circle (third arg= gray value: 0=black, 1=white). The possible
   key-value pairs are:
    {\tt rad={\sl expr};} and
    {\tt circle={\sl attributes};} }
\macrodef{dot3D}{dot3D}{({\sl x1,y1,z1,x2,y2,z2})}
  {3D}
  {dot product of two triples}
\macrodef{dotrad\_}{dotrad_}{}
  {gen}
  {dot radius}
\macrodef{down\_}{down_}{}
  {gen}
  {sets current direction to down \seesect{Placing:}}
\macrodef{dright}{dright}{}
  {darrow}
  {double arrow right turn}
\macrodef{drjust}{drjust}{(at {\sl location})}
  {darrow}
  {rjust (displaced dlinewid/2)}
\macrodef{dswitch}{dswitch}{(\linespec,L|R,W[ud]B {\sl chars})}
  {cct}
  {SPST switch left or right, W=baseline, B=contact blade,
    dB=contact blade to the right of drawing direction,
         Bm = mirror contact blade,
         Bo = contact blade more widely open,
         Cb = circuit-breaker function,
         Co = contactor function,
         C = external operating mechanism,
         D = circle at contact and hinge,
             (dD = hinge only, uD = contact only)
         E = emergency button,
         EL = early close (or late open),
         LE = late close (or early open),
         F = fused,
         H = time delay closing,
         uH = time delay opening,
         HH = time delay opening and closing,
         K=vertical closing contact line,
         L = limit,
         M = maintained (latched),
         MM = momentary contact on make,
         MR = momentary contact on release,
         MMR = momentary contact on make and release,
         O = hand operation button,
         P = pushbutton,
         Pr{\tt [T|M]} = proximity (touch-sensitive or magnetically controlled),
         Th = thermal control linkage,
         Tr = tripping,
         Y = pull switch,
         Z = turn switch
   \seesect{Twoterminal:}}
\macrodef{dtee}{dtee}{([L|R])}
  {darrow}
  {double arrow tee junction with tail to left,
   right, or (default) back along current direction }
\macrodef{dtor\_}{dtor_}{}
  {gen}
  {degrees to radians conversion constant}
\macrodef{dturn}{dturn}{({\sl degrees ccw})}
  {darrow}
  {turn dline arg1 degrees left (ccw)}
\Letter{E}%
\macrodef{E\_\_}{E__}{}
  {gen}
  {the constant $e$}
\macrodef{e\_}{e_}{}
  {gen}
  {.e relative to current direction}
\macrodef{e\_fet}{e_fet}{(\linespec,R,P,E|S)}
  {cct}
  {left or right, N or P enhancement MOSFET, normal
   or simplified, without or with envelope
    \seesect{Semiconductors:}}
\macrodef{earphone}{earphone}{( U|D|L|R|{\sl degrees, size})}
  {cct}
  {earphone, {\sl In1} to {\sl In3} defined
   \seesect{Composite:}}
\macrodef{ebox}{ebox}{(\linespec,{\sl lgth},{\sl wdth},{\sl fill value},
  {\sl box attributes})}
  {cct}
  { two-terminal box element with adjustable dimensions and fill
   value 0 (black) to 1 (white). {\sl lgth} (length) and {\sl wdth} (width)
   are relative
   to the direction of \linespec. Alternatively, argument 1 is the
   \linespec\ and argument 2 is a semicolon-separated sequence of key=value
   terms.  The possible keys are {\tt lgth, wdth, text, box},
   e.g., {\tt lgth=0.2; text=\char34{}XX\char34;
     box=shaded \char34{}green\char34}\seesect{Twoterminal:}}
\macrodef{elchop}{elchop}{({\sl Name1,Name2})}
  {gen}
  {{\tt chop} for ellipses: evaluates to {\tt chop} $r$ where $r$ is
    the distance from the centre of ellipse Name1 to the intersection of
    the ellipse with a line to location Name2;
    e.g., {\tt line from A to E elchop(E,A)}}
\macrodef{eleminit\_}{eleminit_}{(\linespec)}
  {cct}
  {internal line initialization}
\macrodef{elen\_}{elen_}{}
  {cct}
  {default element length}
\macrodef{em\_arrows}{em_arrows}{({\sl type}|{\sl keys,angle,length})}
  {cct}
  { Radiation arrows: {\sl type} {\tt N|I|E [D|T]}
  {\tt N}=nonionizing, {\tt I}=ionizing, {\tt E}=simple;
  {\tt D}=dot on arrow stem; {\tt T}=anchor tail;
  {\sl keys:} {\tt type=}{\sl chars} as above;
  {\tt lgth}={\sl expr};
  {\tt sep}={\sl expr}; arrow separation
  {\tt angle}={\sl degrees}; absolute direction\seesect{Twoterminal:}}
\macrodef{endshade}{endshade}{}
  {gen}
  {end gray shading, see {\tt beginshade}}
\macrodef{Equidist3}{Equidist3}{({\sl Pos1, Pos2, Pos3, Result, distance})}
  {gen}
  {Calculates location named {\sl Result} equidistant from the first three
   positions, i.e.\ the centre of the circle passing through the three
   positions.  If arg5 is nonblank, it is equated to the radius.}
\macrodef{expe}{expe}{}
  {gen}
  {exponential, base $e$}
\Letter{F}%
\macrodef{f\_box}{f_box}{({\sl boxspecs},{\sl text},{\sl expr1},$\cdots$)}
  {gen}
  {like {\tt s\_box} but the text is overlaid on a box of identical size.
   If there is only one argument then the default box
   is invisible and filed white
    \seesect{Interaction:}}
\macrodef{Fector}{Fector}{({\sl x1,y1,z1,x2,y2,z2})}
  {3D}
  {vector projected on current view plane with top face
   of 3-dimensonal arrowhead normal to x2,y2,z2 }
\macrodef{Fe\_fet}{Fe_fet}{(\linespec,R,{\sl chars})}
  {cct}
  {FET with superimposed ferroelectric symbol. Args 1 to 3 are as for
   the {\tt mosfet} macro
    \seesect{Semiconductors:}}
\macrodef{FF\_ht}{FF_ht}{}
  {cct}
  {flipflop height parameter in {\tt L\_unit}s}
\macrodef{FF\_wid}{FF_wid}{}
  {cct}
  {flipflop width parameter in {\tt L\_unit}s}
\macrodef{fill\_}{fill_}{({\sl number})}
  {gen}
  {fill macro, 0=black, 1=white\seesect{Semiconductors:}}
\macrodef{fitcurve}{fitcurve}{(V,n,[e.g. dotted],m (default 0))}
  {gen}
  {Draw a spline through positions V[m], $ldots$ V[n]: Works only with dpic.}
\macrodef{FlipFlop}{FlipFlop}{(D|T|RS|JK,{\sl label},{\sl boxspec},%
 {\sl pinlength})}
  {log}
  {flip-flops,
  {\sl boxspec}=e.g.\ ht x wid y \seesect{Logicgates:}}
\macrodef{FlipFlop6}{FlipFlop6}{({\sl label},{\sl spec},{\sl boxspec})}
  {log}
  {{\em This macro (6-input flip-flops)
    has been superseded by {\tt FlipFlopX} and may be deleted
    in future}.
    {\sl spec}={\tt [[n]NQ][[n]Q][[n]CK][[n]PR][lb]}
    {\tt [[n]CLR][[n]S][[n].|D|T|R]} to include and negate pins,
    {\tt lb} to print labels }
\macrodef{FlipFlopJK}{FlipFlopJK}{({\sl label}, {\sl spec},{\sl boxspec})}
  {log}
  {{\em This macro (JK flip-flop)
    has been superseded by {\tt FlipFlopX} and may be deleted
    in future}.
   Similar to {\tt FlipFlop6}.}
\macrodef{FlipFlopX}{FlipFlopX}{({\sl boxspec, label, leftpins, toppins,
   rightpins, bottompins, pinlength})}
  {log}
  {General flipflop.
   Arg 1 modifies the box (labelled Chip) default specification.
   Each of args 3 to 6 is null or a string of {\sl pinspecs}
   separated by semicolons ({\tt;}).  A {\sl Pinspec} is either empty
   or of the form
   {\tt[}{\sl pinopts}{\tt]:[}{\sl label}{\tt[:}{\sl Picname}{\tt]]}.
   The first colon draws the pin.
   Pins are placed top to bottom or left to right along the box edges with
   null {\sl pinspecs} counted for placement. Pins are named by side and number
   by default; eg {\tt W1, W2, ..., N1, N2, ..., E1, ..., S1, ...} ; however,
   if {\tt:}{\sl Picname} is present in a {\sl pinspec} then {\sl Picname}
   replaces the default name.
   A {\sl pinspec} label is text placed at the pin base. Semicolons are
   not allowed in labels; use, e.g., {\tt \char92{}char59\char123\char125}
   instead.
   To put a bar over a label, use {\tt lg\_bartxt(}{\sl label}{\tt)}.
   The {\sl pinopts} are {\tt[N|L|M][E]};
 {\tt N}=pin with not circle;
 {\tt L}=active low out; {\tt M}=active low in;
 {\tt E}=edge trigger \seesect{Logicgates:}. Optional arg 7 is the length
 of pins}
\macrodef{for\_}{for_}{({\sl start},{\sl end},{\sl increment},`{\sl actions}')}
  {gen}
  {integer for loop with index variable {\tt m4x} \seesect{Looping:}}
\macrodef{foreach\_}{foreach_}{(`{\sl variable}',{\sl actions},{\sl
  value1, value2, $\ldots$})}
  {gen}
  {Clone of Loopover\_ by a different name:
   Repeat {\sl actions} with {\sl variable} set successively to
   {\sl value1, value2, $\ldots$}, setting macro {\tt m4Lx} to 1, 2,
   $\ldots$, terminating if {\sl variable} is nul}
\macrodef{FTcap}{FTcap}{({\sl chars})}
  {cct}
  {Feed-through capacitor; example of a composite element derived from
   a two-terminal element.  Defined points: {\sl .Start, .End, .C .T1 .T2 T}
   Arg 1: (default) {\tt A}= type A, {\tt B}= type B, {\tt C}= type C 
   \seesect{Composite:}}
\macrodef{fuse}{fuse}{({\sl linespec, type, wid, ht})}
  {cct}
  {fuse symbol, type$=$
  {\tt  A|B|C|D|S|HB|HC|SB} or {\tt dA=D}\seesect{Twoterminal:}}
\Letter{G}%
\macrodef{g\_}{g_}{}
  {gen}
  {green color value}
\macrodef{G\_hht}{G_hht}{}
  {log}
  {gate half-height in {\tt L\_unit}s}
\macrodef{g\_fet}{g_fet}{(\linespec,R,P,{\sl shade spec})}
  {cct}
  {left or right, N or P graphene FET, without or with shading
    \seesect{Semiconductors:}}
\macrodef{gap}{gap}{(\linespec,{\sl fill},A)}
  {cct}
  {gap with (filled) dots, A=chopped arrow between dots\seesect{Twoterminal:}}
\macrodef{gen\_init}{gen_init}{}
  {gen}
  {initialize environment for general diagrams
    (customizable, reads {\tt libgen.m4})}
\macrodef{glabel\_}{glabel_}{}
  {cct}
  {internal general labeller}
%\macrodef{gpar\_}{gpar_}{({\sl element},{\sl element},{\sl separation})}
%  {cct}
%  {two same-direction elements in parallel}
\macrodef{gpolyline\_}{gpolyline_}{({\sl fraction},{\sl location}, ...)}
  {gen}
  {internal to {\tt gshade}}
\macrodef{graystring}{graystring}{({\sl gray value})}
  {gen}
  {evaluates to a string compatible with the postprocessor in use
   to go with {\tt colored}, {\tt shaded}, or {\tt outlined} attributes.
   (PSTricks, metapost, pgf-tikz, pdf, postscript, svg).
   The argument is a fraction in the range $[0,1]$; see {\tt rgbstring}}
\macrodef{grid\_}{grid_}{({\sl x},{\sl y})}
  {log}
  {absolute grid location}
\macrodef{ground}{ground}{(at {\sl location}, T|{\sl stem length},
   N|F|S|L|P[A]|E, U|D|L|R|{\sl degrees})}
  {cct}
  { ground, without stem for 2nd arg = T;
    {\tt N}=normal, {\tt F}=frame, {\tt S}=signal, {\tt L}=low-noise,
    {\tt P}=protective,
    {\tt PA}=protective alternate,
    {\tt E}=European; up, down, left, right, or angle
    from horizontal (default -90) 
   \seesect{Composite:}}
\macrodef{gshade}{gshade}{({\sl gray value},A,B,...,Z,A,B)}
  {gen}
  {(Note last two arguments).  Shade a polygon with named
    vertices, attempting to avoid sharp corners}
\macrodef{gyrator}{gyrator}{({\sl box specs,space ratio,pin lgth,}[N][V])}
  {cct}
  {Gyrator two-port wrapper for {\tt nport}, {\tt N} omits pin dots; {\tt V}
   gives a vertical orientation
   \seesect{Composite:}}
\Letter{H}%
\macrodef{H\_ht}{H_ht}{}
  {log}
  {hysteresis symbol dimension in {\tt L\_unit}s}
\macrodef{Header}{Header}{(1|2,{\sl rows,wid,ht,box attributes})}
  {log}
  {Header block with 1 or 2 columns and square Pin 1:
   arg1 = number of columns;
   arg2 = pins per column;
   arg3,4 = custom wid, ht;
   arg5 = e.g., {\tt fill\_(0.9)}
    \seesect{Composite:}}
\macrodef{HeaderPin}{HeaderPin}{({\sl location, type, Picname},%
n|e|s|w,{\sl length})}
  {log}
  {General pin for {\tt Header} macro; arg 4 specifies pin direction
   with respect to the current drawing direction)}
\macrodef{hatchbox}{hatchbox}{({\sl boxspec,hashsep,hatchspec})}
  {gen}
  {Manhattan box with 45 degree hatching, e.g.,
   {\tt hatchbox(outlined "blue",,dashed outlined "green" thick 0.4)}}
\macrodef{heater}{heater}{({\sl linespec, ndivisions|keys, wid, ht,
    boxspec}|[E[R][T]])}
  {cct}
  {Heater element\seesect{Twoterminal:}. If arg 5 contains {\tt E,}
    draws an {\tt heatere({\sl linespec, keys,} [R][T]),}
    otherwise a
    {\tt heatert({\sl linespec, nparts, wid, ht, boxspec})}} 
\macrodef{heatere}{heatere}{({\sl linespec, keys,} [R][T])}
  {cct}
  {Heater element with curved sides\seesect{Twoterminal:}.
    {\tt R} means right orientation;
    {\tt T} truncates leads to the width of the body.
    The {\sl keys} for the body are
    {\tt lgth={\sl expr};}
    {\tt wdth={\sl expr};} (default {\tt lgth*2/5});
    {\tt cycles={\sl expr};}
    {\tt line={\sl attributes};} (e.g., {\tt dotted, dashed, outlined})}
\macrodef{heatert}{heatert}{({\sl linespec, nparts|keys, wid, ht, boxspec})}
  {cct}
  {Two-terminal rectangular heater element\seesect{Twoterminal:}.
    The {\sl keys} for the body are
    {\tt parts={\sl expr};}
    {\tt lgth={\sl expr};}
    {\tt wdth={\sl expr};} (default {\tt lgth*2/5});
    {\tt box={\sl body attributes};}
      (e.g., {\tt dotted, dashed, outlined, shaded}).
    Args 3--5 are unused if any key is given}
\macrodef{hex\_digit}{hex_digit}{($n$)}
  {gen}
  {hexadecimal digit for $0 \leq n < 16$}
\macrodef{hexadecimal\_}{hexadecimal_}{($n$, [$m$])}
  {gen}
  {hexadecimal representation of $n,$ left padded to $m$ digits if the second
   argument is nonblank}
\macrodef{hlth}{hlth}{}
  {gen}
  {current line half thickness in drawing units}
\macrodef{hoprad\_}{hoprad_}{}
  {cct}
  {hop radius in crossover macro}
\macrodef{ht\_}{ht_}{}
  {gen}
  {height relative to current direction}
\Letter{I}%
\macrodef{ifdpic}{ifdpic}{({\sl if true},{\sl if false})}
  {gen}
  {test if dpic has been specified as pic processor}
\macrodef{ifgpic}{ifgpic}{({\sl if true},{\sl if false})}
  {gen}
  {test if gpic has been specified as pic processor}
\macrodef{ifinstr}{ifinstr}{({\sl string},{\sl string},{\sl if true},{\sl
    if false})}
  {gen}
  {test if the second argument is a substring of the first; also
  {\tt ifinstr({\sl string},{\sl string},{\sl if true},{\sl
  string},{\sl string},{\sl if true}, $\ldots$ {\sl if false})}
    }
\macrodef{ifmfpic}{ifmfpic}{({\sl if true},{\sl if false})}
  {gen}
  {test if mfpic has been specified as pic post-processor}
\macrodef{ifmpost}{ifmpost}{({\sl if true},{\sl if false})}
  {gen}
  {test if MetaPost has been specified as pic post-processor}
\macrodef{ifpgf}{ifpgf}{({\sl if true},{\sl if false})}
  {gen}
  {test if \TPGF~has been specified as pic post-processor}
\macrodef{ifpostscript}{ifpostscript}{({\sl if true},{\sl if false})}
  {gen}
  {test if Postscript ({\tt dpic -r}) has been specified as pic output format}
\macrodef{ifpsfrag}{ifpsfrag}{({\sl if true},{\sl if false})}
  {gen}
  {Test if either {\tt psfrag} or {\tt psfrag\_} has been defined. For
   postscript with psfrag strings, one or the other should be defined
   prior to or at the beginning of the diagram}
\macrodef{ifpstricks}{ifpstricks}{({\sl if true},{\sl if false})}
  {gen}
  {test if \PSTricks~has been specified as post-processor}
\macrodef{ifroff}{ifroff}{({\sl if true},{\sl if false})}
  {gen}
  {test if {\bf troff} or {\bf groff} has been specified as post-processor}
\macrodef{ifxfig}{ifxfig}{({\sl if true},{\sl if false})}
  {gen}
  {test if Fig 3.2 ({\tt dpic -x}) has been specified as pic output format}
\macrodef{igbt}{igbt}{(\linespec,L|R,[L][[d]D])}
  {cct}
  {left or right IGBT, L=alternate gate type, D=parallel diode,
   dD=dotted connections }
\macrodef{in\_\_}{in__}{}
  {gen}
  {absolute inches}
\macrodef{inductor}{inductor}{(\linespec, W|L, {\sl cycles}, M[n]|P[n]|K[n],
   {\sl loop wid})}
  {cct}
  {inductor, arg2: narrow (default), W=wide, L=looped;
   arg3: number of arcs or cycles (default 4);
   arg4: M=magnetic core, P=powder (dashed) core, K=long-dashed core,
     n={\sl integer} (default 2) number of core lines named
     {\sl M4Core1, M4Core2,} $\ldots$;
   arg5: loop width (default L,W: {\tt dimen\_}/5; other: {\tt dimen\_}/8)
   \seesect{Twoterminal:}}
\macrodef{inner\_prod}{inner_prod}{({\sl linear obj},{\sl linear obj})}
  {gen}
  {inner product of (x,y) dimensions of two linear objects}
\macrodef{Int\_}{Int_}{}
  {gen}
  {corrected (old) gpic $int()$ function}
\macrodef{integrator}{integrator}{(\linespec,{\sl size})}
  {cct}
  {integrating amplifier\seesect{Twoterminal:}}
\macrodef{intersect\_}{intersect_}{({\sl line1}.start,{\sl line1}.end,
{\sl line2}.start,{\sl line2}.end)}
  {gen}
  {intersection of two lines}
\macrodef{Intersect\_}{Intersect_}{({\sl Name1},{\sl Name2})}
  {gen}
  {intersection of two named lines}
\macrodef{IOdefs}{IOdefs}{(\linespec,{\sl label},[P|N]*,L|R) }
  {log}
  {Define locations {\sl label}{\tt 1}, $\ldots$ {\sl label}{\tt n}
    along the line; {\tt P}= label only;
    {\tt N}=with {\tt NOT\_circle};
    {\tt R}=circle to right of current direction }
\Letter{J}%
\macrodef{j\_fet}{j_fet}{(\linespec,L|R,P,E)}
  {cct}
  {left or right, N or P JFET, without or with envelope
    \seesect{Semiconductors:}}
\macrodef{jack}{jack}{(U|D|L|R|{\sl degrees},{\sl chars})}
  {cct}
  {arg1: drawing direction; string arg2: {\tt R}=right orientation,
   one or more {\tt L[M][B]} for L and auxiliary contacts with make or break
   points; {\tt S[M][B]} for S and auxiliary contacts
   \seesect{Composite:}}
\macrodef{jumper}{jumper}{({\sl linespec, chars}|{\sl keys})}
  {cct}
  { Two-terminal solder jumper with named body parts.
    The {\sl chars} character sequence specifies the jumper components,
    and normally begins with {\tt C} and ends with {\tt D.} The character
    {\tt E} is an empty (blank) gap, {\tt J} is a filled gap, {\tt B}
    is a box component.  The components are named {\sl T1, T2, \ldots}
    Examples: {\tt CED} is a simple open jumper (the default); {\tt CJD}
    closed; {\tt CEBED} three-contact open; {\tt CJBED} three-contact
    open and closed.
    The {\sl keys} are: {\tt type=}{\sl chars} as previously;
                        {\tt body=}{\sl attributes} (e.g. {\tt fill\_(0.5)});
                        {\tt wdth=}{\sl expr};
                        {\tt name=}{\sl chars} (the body name)%
\seesect{Twoterminal:}}
\Letter{K}%
\macrodef{KelvinR}{KelvinR}{({\sl cycles},[R],{\sl cycle wid})}
  {cct}
  {IEEE resistor in a {\tt [ ]} block with Kelvin taps {\sl T1} and {\sl T2}
   \seesect{Composite:}}
\Letter{L}%
\macrodef{L\_unit}{L_unit}{}
  {log}
  {logic-element grid size}
\macrodef{lamp}{lamp}{(\linespec, [R][T])}
  {cct}
  {Two-terminal incandescent lamp. {\tt T} truncates leads to the body width.
   \seesect{Twoterminal:}}
\macrodef{larrow}{larrow}{({\sl label},{\tt ->|<-},{\sl dist})}
  {cct}
  {arrow {\sl dist} to left of last-drawn 2-terminal element
   \seesect{Branchcurrent:}}
\macrodef{lbox}{lbox}{({\sl wid}, {\sl ht}, {\sl attributes})}
  {gen}
  {box oriented in current direction, arg 3= e.g.\ {\tt dashed shaded "red"}}
\macrodef{LCintersect}{LCintersect}{({\sl line name, Centre, rad,} [R])}
  {gen}
  { First (second if arg4 is R) intersection of a line with a circle}
\macrodef{LCtangent}{LCtangent}{({\sl Pos1, Centre, rad,} [R])}
  {gen}
  { Left (right if arg4=R) tangent point of line
     from Pos1 to circle at Centre with radius arg3}
\macrodef{left\_}{left_}{}
  {gen}
  {left with respect to current direction \seesect{Placing:}}
\macrodef{length3D}{length3D}{(x,y,z)}
  {3D}
  {Euclidean length of triple x,y,z}
\macrodef{LEintersect}{LEintersect}{({\sl line name, Centre, ellipse wid,
  ellipse ht}, [R])}
  {gen}
  { First (second if arg5 is R) intersection of a line with an ellipse}
\macrodef{LEtangent}{LEtangent}{({\sl Pos1, Centre, ellips wid, ellipse ht}
 [R])}
  {gen}
  { Left (right if arg5=R) tangent point of line
     from Pos1 to ellipse at Centre with given width and height}
\macrodef{lg\_bartxt}{lg_bartxt}{}
  {log}
  {draws an overline over logic-pin text (except for xfig)}
\macrodef{lg\_pin}{lg_pin}{({\sl location, label, Picname},
  n|e|s|w[L|M|I|O][N][E], {\sl pinno, optlen})}
  {log}
  {comprehensive logic pin;
   {\sl label}= text (indicating logical pin function, usually),
   {\sl Picname}= pic label for referring to the pin (line),
   {\tt n|e|s|w}=orientation (north, south, east, west),
   {\tt L}=active low out,
   {\tt M}=active low in,
   {\tt I}=inward arrow,
   {\tt O}=outward arrow,
   {\tt N}=negated,
   {\tt E}=edge trigger}
\macrodef{lg\_pintxt}{lg_pintxt}{}
  {log}
  {reduced-size text for logic pins}
\macrodef{lg\_plen}{lg_plen}{}
  {log}
  {logic pin length in in {\tt L\_unit}s}
\macrodef{LH\_symbol}{LH_symbol}{([U|D|L|R|{\sl degrees}][I])}
  {log}
  {logic-gate hysteresis symbol; {\tt I=}inverted}
\macrodef{lin\_ang}{lin_ang}{({\sl line-reference}[,d])}
  {gen}
  {the angle of a line or move from {\tt .start} to {\tt .end} of a linear
   object (in degrees if arg2={\tt d})}
\macrodef{lin\_leng}{lin_leng}{({\sl line-reference})}
  {gen}
  {length of a line, equivalent to {\sl line-reference}{\tt .len}
   with dpic}
\macrodef{linethick\_}{linethick_}{({\sl number})}
  {gen}
  {set line thickness in points}
\macrodef{ljust\_}{ljust_}{}
  {gen}
  {ljust with respect to current direction}
\macrodef{llabel}{llabel}{({\sl label},{\sl label},{\sl label},[{\sl arg4}],%
    [{\sl block name}])}
  {cct}
  {Triple label on the left of the body of an element with respect to the
    current direction \seesect{Labels:}.  Labels are placed at the
    beginning, centre, and end of the last {\tt []} block (or a named
    {\tt []} block). Each label is treated as math by default, but is
    copied literally if it is in double quotes or defined by sprintf.
    {\sl Arg4} can be {\tt above,} {\tt below,} {\tt left,} or {\tt
    right} to supplement the default relative position.  The fifth
    argument is the optional name of the {\tt []} block to be labelled,
    which is {\tt last []} by default}
\macrodef{loc\_}{loc_}{({\sl x}, {\sl y})}
  {gen}
  {location adjusted for current direction}
\macrodef{log\_init}{log_init}{}
  {log}
  {initialize environment for logic diagrams
    (customizable, reads {\tt liblog.m4})}
\macrodef{log10E\_}{log10E_}{}
  {gen}
  {constant $\log_{10}(e)$}
\macrodef{loge}{loge}{}
  {gen}
  {logarithm, base $e$}
\macrodef{Loopover\_}{Loopover_}{(`{\sl variable}',{\sl actions},{\sl
  value1, value2, $\ldots$})}
  {gen}
  {Repeat {\sl actions} with {\sl variable} set successively to
   {\sl value1, value2, $\ldots$}, setting macro {\tt m4Lx} to 1, 2,
   $\ldots$, terminating if {\sl variable} is nul}
\macrodef{lp\_xy}{lp_xy}{}
  {log}
  {coordinates used by {\tt lg\_pin}}
\macrodef{lpop}{lpop}{({\sl xcoord}, {\sl ycoord}, {\sl radius},
{\sl fill},
  {\sl zero ht})} {gen}
  {for lollipop graphs: filled circle with stem to
  (xcoord,zeroht)}
\macrodef{lswitch}{lswitch}{( \linespec, L|R, {\sl chars} )}
  {cct}
  {knife switch R=right orientation (default L=left);
    {\sl chars}=[O{\tt|}C][D][K][A] O=opening arrow; C=closing arrow;
    D=dots; K=closed switch; A=blade arrowhead \seesect{Twoterminal:}}
\macrodef{lt\_}{lt_}{}
  {gen}
  {left with respect to current direction}
\macrodef{LT\_symbol}{LT_symbol}{(U|D|L|R|{\sl degrees})}
  {log}
  {logic-gate triangle symbol}
\macrodef{lthick}{lthick}{}
  {gen}
  {current line thickness in drawing units}
\Letter{M}%
\macrodef{m4\_arrow}{m4_arrow}{(\linespec,{\sl ht},{\sl wid})}
  {gen}
  {arrow with adjustable head, filled when possible}
\macrodef{m4dupstr}{m4dupstr}{({\sl string},{\sl n},`{\sl name}')}
  {gen}
  {Defines {\sl name} as {\sl n} concatenated copies of {\sl
  string}.}
\macrodef{m4lstring}{m4lstring}{({\sl arg1},{\sl arg2})}
  {gen}
  {expand {\sl arg1} if it begins
    with {\tt sprintf} or {\tt "}, otherwise {\sl arg2}}
\macrodef{m4xpand}{m4xpand}{({\sl arg})}
  {gen}
  {Evaluate the argument as a macro}
\macrodef{m4xtract}{m4xtract}{(`{\sl string1}',{\sl string2})}
  {gen}
  {delete {\sl string2} from {\sl string1}, return 1 if present}
\macrodef{manhattan}{manhattan}{}
  {gen}
  {sets direction cosines for left, right, up, down}
\macrodef{Max}{Max}{({\sl arg, arg, $\ldots$})}
  {gen}
  {Max of an arbitrary number of inputs}
\macrodef{memristor}{memristor}{({\sl linespec, wid, ht})}
  {cct}
  {memristor element\seesect{Twoterminal:}}
\macrodef{microphone}{microphone}{( A|U|D|L|R|{\sl degrees, size})}
  {cct}
  {microphone; if arg1 = A: upright mic, otherwise arg1 sets
  direction
   of standard microphone with {\sl In1} to {\sl In3} defined
   \seesect{Composite:}}
\macrodef{Min}{Min}{({\sl arg, arg, $\ldots$})}
  {gen}
  {Min of an arbitrary number of inputs}
\macrodef{Mitre\_}{Mitre_}{%
 ({\sl Line1,Line2,length,line attributes})}
  {gen}
  {e.g., {\tt Mitre\_(L,M)} draws angle at intersection of lines
   L and M with legs of length arg3 (default {\tt linethick bp\_\_/2});
   sets {\tt Here} to intersection
    \seesect{Corners:}}
\macrodef{mitre\_}{mitre_}{%
 ({\sl Position1,Position2,Position3,length,line attributes})}
  {gen}
  {e.g., {\tt mitre\_(A,B,C)} draws angle ABC with legs
   of length arg4 (default {\tt linethick bp\_\_/2}); sets {\tt Here}
   to Position2
    \seesect{Corners:}}
\macrodef{mm\_\_}{mm__}{}
  {gen}
  {absolute millimetres}
\macrodef{mosfet}{mosfet}{(\linespec,L|R,{\sl chars},E)}
  {cct}
  {MOSFET left or right, included components defined by characters,
  envelope.
   arg 3 chars:
   {\tt [u][d]B:} center bulk connection pin;
   {\tt D:} D pin and lead;
   {\tt E:} dashed substrate;
   {\tt F:} solid-line substrate;
   {\tt [u][d]G:} G pin to substrate at source;
   {\tt [u][d]H:} G pin to substrate at center;
   {\tt L:} G pin to channel (obsolete);
   {\tt [u][d]M:} G pin to channel, u: at drain end, d: at source end;
   {\tt [u][d]M{\sl n}:} multiple gates G0 to G{\sl n};
   {\tt Py:} parallel diode;
   {\tt Pz:} parallel zener diode;
   {\tt Q:} connect B pin to S pin;
   {\tt R:} thick channel;
   {\tt [u][d]S:} S pin and lead u: arrow up, d: arrow down;
   {\tt [d]T:} G pin to center of channel d: not circle;
   {\tt X:} XMOSFET terminal;
   {\tt Z:} simplified complementary MOS
   \seesect{Semiconductors:}}
\macrodef{Mux\_ht}{Mux_ht}{}
  {cct}
  {Mux height parameter in {\tt L\_unit}s}
\macrodef{Mux\_wid}{Mux_wid}{}
  {cct}
  {Mux width parameter in {\tt L\_unit}s}
\macrodef{Mux}{Mux}{({\sl n},{\sl label},
   {\tt [L][B|H|X][N[{\sl n}]|S[{\sl n}]][[N]OE], {\sl wid},{\sl ht}})}
  {log}
  {binary multiplexer, $n$ inputs,
    {\tt L} reverses input pin numbers, {\tt B} display binary pin
    numbers, {\tt H} display hexadecimal pin numbers, {\tt X} do not
    print pin numbers, {\tt N[{\sl n}]} puts Sel or Sel$0$ .. Sel$n$
    at the top (i.e., to the left of the drawing direction), {\tt
    S[{\sl n}]} puts the Sel inputs at the bottom (default) {\tt OE}
    ({\tt N=}negated) {\tt OE} pin \seesect{Logicgates:}}
\macrodef{Mx\_pins}{Mx_pins}{}
  {log}
  {max number of gate inputs without wings}
\Letter{N}%
\macrodef{n\_}{n_}{}
  {gen}
  {.n with respect to current direction}
\macrodef{N\_diam}{N_diam}{}
  {log}
  {diameter of `not' circles in {\tt L\_unit}s}
\macrodef{N\_rad}{N_rad}{}
  {log}
  {radius of `not' circles in {\tt L\_unit}s}
\macrodef{NAND\_gate}{NAND_gate}{({\sl n},N)}
  {log}
  {`nand' gate, 2 or {\sl n\/} inputs; N=negated input.
   Otherwise, arg1 can be a sequence of letters {\tt P|N} to define
   normal or negated inputs.
    \seesect{Logicgates:}}
\macrodef{ne\_}{ne_}{}
  {gen}
  {.ne with respect to current direction}
\macrodef{NeedDpicTools}{NeedDpicTools}{}
  {gen}
  {executes {\tt copy "HOMELIB\_/dpictools.pic"} if the file has
  not been read}
\macrodef{neg\_}{neg_}{}
  {gen}
  {unary negation}
\macrodef{NOR\_gate}{NOR_gate}{({\sl n},N)}
  {log}
  {`nor' gate, 2 or {\sl n\/} inputs; N=negated input.
   Otherwise, arg1 can be a sequence of letters {\tt P|N} to define
   normal or negated inputs.
    \seesect{Logicgates:}}
\macrodef{norator}{norator}{(\linespec,{\sl width},{\sl ht})}
  {cct}
  { norator two-terminal element \seesect{Twoterminal:}}
\macrodef{NOT\_circle}{NOT_circle}{}
  {log}
  {`not' circle}
\macrodef{NOT\_gate}{NOT_gate}{(\linespec,[B][N|n],{\sl wid},{\sl
height})}
  {log}
  {`not' gate.
   When {\sl linespec} is blank then the element is composite and In1,
   Out, C, NE, and SE are defined; otherwise the element is drawn as a
   two-terminal element. arg2: {\tt B}=box gate, {\tt N}=not circle at
   input and output, {\tt n}=not circle at input only
    \seesect{Logicgates:}}
\macrodef{NOT\_rad}{NOT_rad}{}
  {log}
  {`not' radius in absolute units}
\macrodef{NPDT}{NPDT}{({\sl npoles,}[R])}
  {cct}
  {Double-throw switch; {\sl npoles:} number of poles;
   {\tt R}= right orientation with respect to drawing direction
   \seesect{Composite:}}
\macrodef{nport}{nport}{({\sl box spec{\tt ;}other commands,
nw,nn,ne,ns,space ratio,pin lgth,style, other commands})}
  {cct}
  { Default is a standard-box twoport.  Args 2 to 5 are
    the number of ports to be drawn on w, n, e, s sides.  The port pins
    are named by side, number, and by a or b pin, e.g., W1a, W1b, W2a,
    $\ldots$ Arg 6 specifies the ratio of port width to interport space
    (default 2), and arg 7 is the pin length.  Set arg 8 to N to omit
    the dots on the port pins. Arguments 1 and 9 allow customizations
   \seesect{Composite:}}
\macrodef{nterm}{nterm}{({\sl box spec{\tt ;}other commands,
nw,nn,ne,ns,pin lgth,style, other commands})}
  {cct}
  {n-terminal box macro (default three pins).
   Args 2 to 5 are the number of pins to be drawn on W, N, E, S
   sides.  The pins are named by side and number, e.g. W1, W2, N1,
   $\ldots$ Arg 6 is the pin length.  Set arg 7 to N to omit the
   dots on the pins. Arguments 1 and 8 allow customizations, e.g.
   {\tt nterm(,{,},{,},{,}N,"\$a\$" at Box.w ljust,"\$b\$" at Box.e rjust,
      "\$c\$" at Box.s above)} }
\macrodef{nullator}{nullator}{(\linespec,{\sl width},{\sl ht})}
  {cct}
  { nullator two-terminal element \seesect{Twoterminal:}}
\macrodef{nw\_}{nw_}{}
  {gen}
  {.nw with respect to current direction}
\macrodef{NXOR\_gate}{NXOR_gate}{({\sl n},N)}
  {log}
  {`nxor' gate, 2 or {\sl n\/} inputs; N=negated input.
   Otherwise, arg1 can be a sequence of letters {\tt P|N} to define
   normal or negated inputs.
    \seesect{Logicgates:}}
\Letter{O}%
\macrodef{opamp}{opamp}{(\linespec,{\sl label},{\sl
label},{\sl size},{\sl
    chars}, other commands)}
  {cct}
  {operational amplifier with $-,$ $+$ or other internal labels,
    specified size. {\sl chars:} {\tt P=} add power connections, {\tt
    R=} swap In1, In2 labels, {\tt T=} truncated point.  The internally
    defined positions are {\sl W, N, E, S, Out, NE, SE, In, In2}, and
    the (obsolete) positions {\sl E1 = NE, E2 = SE}.  The first and last
    arguments allow added customizations
   \seesect{Composite:}}
\macrodef{open\_arrow}{open_arrow}{(\linespec,{\sl ht},{\sl wid})}
  {gen}
  {arrow with adjustable open head}
\macrodef{OR\_gate}{OR_gate}{({\sl n},N)}
  {log}
  {`or' gate, 2 or {\sl n\/} inputs; N=negated input.
   Otherwise, arg1 can be a sequence of letters {\tt P|N} to define
   normal or negated inputs.
    \seesect{Logicgates:}}
\macrodef{OR\_gen}{OR_gen}{($n$,{\sl chars},[{\sl wid},[{\sl ht}]])}
  {log}
  {general OR gate: $n$=number of inputs $(0\leq n\leq 16)$;
    {\sl chars:} B=base and straight sides; A=Arcs;
           [N]NE,[N]SE,[N]I,[N]N,[N]S=inputs or circles; [N]P=XOR arc;
           [N]O=output; C=center.
   Otherwise, arg1 can be a sequence of letters {\tt P|N} to define
   normal or negated inputs.}
\macrodef{OR\_rad}{OR_rad}{}
  {log}
  {radius of OR input face in {\tt L\_unit}s}
\Letter{P}%
\macrodef{parallel\_}{parallel_}{(\char96{\sl
elementspec}\char39,%
 \char96{\sl elementspec}\char39 $\ldots$)}
  {cct}
  { Parallel combination of two-terminal elements in a {\tt [
  ]} block.
    Each argument is a {\em quoted} elementspec of the form {\tt[Sep={\sl
    val};][{\sl Label}:] {\sl element}; [{\sl attributes}]} where
    an {\sl attribute} is of the form {\tt[llabel($\ldots$);] |
    [rlabel($\ldots$);] | [b\_current($\ldots$);]}.  An argument may
    also be {\tt series\_($\ldots$)} or {\tt parallel\_($\ldots$)} {\em
    without} attributes or quotes.  Sep={\sl val}; in the first branch
    sets the default separation of all branches to {\sl val}; in a later
    element Sep={\sl val}; applies only to that branch.  An element may
    have normal arguments but should not change the drawing direction.
   \seesect{Seriesandparallel:}}
%\macrodef{par\_}{par_}{({\sl element},{\sl element},{\sl separation})}
%  {cct} %  {two same-direction, same-length elements in parallel}
\macrodef{proximity}{proximity}{(\sl linespec)}
  {cct}
  {proximity detector (= {\tt consource(,P)})}
\macrodef{pc\_\_}{pc__}{}
  {gen}
  {absolute points}
\macrodef{pvcell}{pvcell}{({\sl linespec, width, height})}
  {cct}
  {PV cell}
\macrodef{px\_\_}{px__}{}
  {gen}
  {absolute SVG screen pixels}
\macrodef{pconnex}{pconnex}{(R|L|U|D|{\sl degrees},{\sl chars})}
  {cct}
  {power connectors, arg 1: drawing direction; {\sl chars:}
   {\tt R}=right orientation, {\tt M|F}= male, female, {\tt A|AC}=115V,
   3 prong, B=box, C=circle, {\tt P}= PC connector, {\tt D}= 2-pin
   connector, {\tt G|GC}= GB 3-pin, {\tt J}= 110V 2-pin
    \seesect{Composite:}}
\macrodef{pi\_}{pi_}{}
  {gen}
  {$\pi$}
\macrodef{plug}{plug}{(U|D|L|R|{\sl degrees},[2|3][R])}
  {cct}
  {arg1: drawing direction; string arg2: {\tt R} right orientation,
   {\tt 2|3} number of conductors \seesect{Composite:}}
\macrodef{pmod}{pmod}{({\sl integer}, {\sl integer})}
  {gen}
  {+ve $\hbox{mod}(M,N)$ e.g., $\hbox{\tt pmod}(-3,5)=2$}
\macrodef{point\_}{point_}{({\sl angle})}
  {gen}
  {(radians) set direction cosines}
\macrodef{perpto}{perpto}{({\sl Pos1, Line, Point})}
  {gen}
  {{\sl Point} is the label for the point on {\sl Line} of the
  perpendicular
   from {\sl Point} to {\sl Line}.}
\macrodef{PerpTo}{PerpTo}{({\sl Pos1, Pos2, Pos3})}
  {gen}
  {The point between Pos2 and Pos3 of intersection of the perpendicular
   to Pos1, i.e., the perpendicular projection of Pos1 onto the line
   from Pos2 to Pos3.}
\macrodef{Point\_}{Point_}{({\sl integer})}
  {gen}
  {sets direction cosines in degrees \seesect{Placing:}}
\macrodef{polar\_}{polar_}{({\sl x},{\sl y})}
  {gen}
  {rectangular-to polar conversion}
\macrodef{langle}{langle}{({\sl Start, End})}
  {gen}
  {Angle in radians from horizontal of the line from {\sl Start}
  to {\sl End}.}
\macrodef{potentiometer}{potentiometer}{(\linespec,%
  {\sl cycles},{\sl fractional pos},{\sl length},$\cdots$)} {cct}
  {resistor with taps T1, T2, $\ldots$
    with specified fractional positions and lengths (possibly neg)
   \seesect{Composite:}}
\macrodef{print3D}{print3D}{(x,y,z)}
  {3D} {write out triple for debugging}
\macrodef{prod\_}{prod_}{({\sl a},{\sl b})}
  {gen}
  {binary multiplication}
\macrodef{project}{project}{({\sl x},({\sl y},({\sl z})}
  {3D} {3D to 2D projection onto the plane perpendicular to the view
  vector with
   angles defined by {\tt setview({\sl azim, elev})}}
\macrodef{psset\_}{psset_}{({\sl PSTricks settings})}
  {gen}
  {set PSTricks parameters}
\macrodef{pt\_\_}{pt__}{}
  {gen}
  {\TeX\ point-size factor, in scaled inches, ({\tt *scale/72.27})}
\macrodef{PtoL}{PtoL}{({\sl position}, U|D|L|R|{\sl degrees}, {\sl length}) }
  {gen}
  {Evaluates to {\tt from {\sl position} to
   {\sl position} + Rect\_({\sl length, angle}) }
   from the polar-coordinate data in the arguments }
\macrodef{ptrans}{ptrans}{(\linespec, [R|L])}
  {cct}
  {pass transistor; {\tt L=} left orientation
    \seesect{Semiconductors:}}
\macrodef{pushkey\_}{pushkey_}{({\sl string, key, default value,}[N])}
  {gen}
  {Key-value definition.
  If {\sl string} contains the substring
  {\sl key}{\tt =}{\sl expr} then macro {\tt m4{\sl key}}
  is defined using {\tt pushdef()} to
  expand to {\tt ({\sl expr})}, or to {\tt ({\sl default value})} if the
  substring is missing.  Arg 1 can contain several such substrings separated
  by semicolons.
  If arg4 is nonblank, the parentheses are omitted.
   \seesect{Macroarguments:}}
\macrodef{pushkeys\_}{pushkeys_}{({\sl string, key sequence})}
  {gen}
  {Multiple key-value definitions. Arg 2 is a semicolon-separated
   sequence of terms of the form {\tt {\sl key}:{\sl default value}:[N]}
   which must contain no semicolons and the default values contain no colons.
   Macro {\tt pushkey\_} is applied to each of the terms in order.
   \seesect{Macroarguments:}}
\Letter{R}%
\macrodef{r\_}{r_}{}
  {gen}
  {red color value}
\macrodef{rarrow}{rarrow}{({\sl label,{\tt ->|<-},{\sl dist}})}
  {cct}
  {arrow {\sl dist} to right of last-drawn 2-terminal element
   \seesect{Branchcurrent:}}
\macrodef{Rect\_}{Rect_}{({\sl radius},{\sl angle})}
  {gen}
  {(deg) polar-to-rectangular conversion}
\macrodef{rect\_}{rect_}{({\sl radius},{\sl angle})}
  {gen}
  {(radians) polar-rectangular conversion}
\macrodef{reed}{reed}{({\sl linespec, width, height, box attribues},
[R][C])}
  {cct}
  {Enclosed reed two-terminal contact;
   {\tt R}=right orientation; {\tt C}=closed contact; e.g., {\tt
   reed(,,dimen\_/5,shaded "lightgreen"} \seesect{Composite:}}
\macrodef{relay}{relay}{({\sl number of poles, chars})}
  {cct}
  {relay: n poles (default 1), {\sl chars:} {\tt O}=normally open,
    {\tt C}=normally closed, {\tt P}=three position, default double
    throw, {\tt L}=drawn left (default), {\tt R}=drawn right, {\tt
    Th}=thermal.  Argument 3={\tt [L|R]} is deprecated but works for
    backward compatibility
   \seesect{Composite:}}
\macrodef{relaycoil}{relaycoil}{({\sl chars, wid, ht,} R|L|U|D|{\sl
degrees})}
  {cct}
  {chars:
    {\tt X}=or default: external lines from A2 and B2; {\tt AX}=external
    lines at positions A1,A3; {\tt BX}=external lines at positions
    B1,B3; {\tt NX}=no lines at positions A1,A2,A3,B1,B2,B3; {\tt
    SO}=slow operating; {\tt SOR}=slow operating and release; {\tt
    SR}=slow release; {\tt HS}=high speed; {\tt NAC}=unaffected by AC
    current; {\tt AC AC}=current; {\tt ML}=mechanically latched; {\tt
    PO}=polarized; {\tt RM}=remanent; {\tt RH}=remanent; {\tt TH}=thermal;
    {\tt EL}=electronic
   \seesect{Composite:}}
\macrodef{resetdir\_}{resetdir_)}{}
  {gen}
  {resets direction set by {\tt setdir\_}}
\macrodef{resetrgb}{resetrgb}{}
  {gen}
  {cancel {\tt r\_, g\_, b\_} color definitions}
\macrodef{resistor}{resistor}{(\linespec,n|E,{\sl chars}, {\sl
    cycle wid})}
  {cct}
  {resistor, n cycles (default 3), {\sl chars:}
    {\tt AC}=general complex element,
    {\tt E}={\tt ebox}, {\tt ES}={\tt ebox} with slash, {\tt Q}=offset,
    {\tt H}=squared, {\tt N}=IEEE, {\tt B}=not burnable, {\tt V}=varistor
    variant, {\tt R}=right-oriented, {\sl cycle width} (default {\tt
    dimen\_}$/6$) \seesect{Twoterminal:}}
\macrodef{resized}{resized}{({\sl factor},`{\sl macro name}',args)}
  {cct}
  {scale the element body size by {\sl factor}}
\macrodef{restorem4dir}{restorem4dir}{([`{\sl stack name}'])}
  {gen}
  {Restore m4 direction parameters from the named stack;
    default {\tt `savm4dir\_'}}
\macrodef{reversed}{reversed}{(`{\sl macro name}',args)}
  {cct}
  {reverse polarity of 2-terminal element}
\macrodef{rgbdraw}{rgbdraw}{({\sl color triple}, {\sl drawing commands})}
  {gen}
  {color drawing for PSTricks, pgf, MetaPost, SVG postprocessors;
   (color entries are 0 to 1),
   see {\tt setrgb} \seesect{Semiconductors:}.  Exceptionally, the color
   of SVG arrows other than the default black has to be defined using the
   {\tt outlined }{\sl string} and {\tt shaded }{\sl string} constructs.}
\macrodef{rgbfill}{rgbfill}{({\sl color triple}, {\sl closed path})}
  {gen}
  {fill with arbitrary color (color entries are 0 to 1); see {\tt
   setrgb}\seesect{Semiconductors:}}
\macrodef{rgbstring}{rgbstring}{({\sl color triple or color name})}
  {gen}
  {evaluates to a string compatible with the postprocessor in use
   to go with {\tt colored}, {\tt shaded}, or {\tt outlined} attributes.
   (PSTricks, metapost, pgf-tikz, pdf, postscript, svg).  The arguments
   are fractions in the range $[0,1]$; For example, {\tt box outlined
   rgbstring(0.1,0.2,0.7) shaded rgbstring(0.75,0.5,0.25)}.  For those
   postprocessors that allow it, there can be one argument which is the
   name of a defined color}
\macrodef{right\_}{right_}{}
  {gen}
  {set current direction right \seesect{Placing:}}
\macrodef{RightAngle}{RightAngle}{({\sl Pos1, Pos2, Pos3, line len,
  attributes})} {gen}
  {Draw a right-angle symbol at {\sl Pos2}, of size
  given by arg4. Arg5 =
   line attributes, e.g., {\tt outlined "gray"}}
\macrodef{r\_text}{r_text}{({\sl degrees},{\sl text},at {\sl position})}
  {gen}
  {Rotate text by arg1 degrees (provides a single command for
   PSTricks, PGF, or SVG only) placed at position in arg3.
   The first argument is a decimal constant (not an expression) and
   the text is a simple string without quotes.
   \seesect{Interaction:}, \seesect{Pstricks:}}
\macrodef{rjust\_}{rjust_}{}
  {gen}
  {right justify with respect to current direction}
\macrodef{rlabel}{rlabel}{({\sl label},{\sl label},{\sl label},[{\sl arg4}],%
    [{\sl block name}])}
  {cct}
  {Triple label on the right of the body of an element with respect to the
    current direction \seesect{Labels:}.  Labels are placed at the
    beginning, centre, and end of the last {\tt []} block (or a named
    {\tt []} block). Each label is treated as math by default, but is
    copied literally if it is in double quotes or defined by sprintf.
    {\sl Arg4} can be {\tt above,} {\tt below,} {\tt left,} or {\tt
    right} to supplement the default relative position.  The fifth
    argument is the optional name of the {\tt []} block to be labelled,
    which is {\tt last []} by default}
\macrodef{rot3Dx}{rot3Dx}{({\sl radians,x,y,z})}
  {3D} {rotates x,y,z about x axis}
\macrodef{rot3Dy}{rot3Dy}{({\sl radians,x,y,z})}
  {3D} {rotates x,y,z about y axis}
\macrodef{rot3Dz}{rot3Dz}{({\sl radians,x,y,z})}
  {3D} {rotates x,y,z about z axis}
\macrodef{Rot\_}{Rot_}{({\sl position, degrees})}
  {gen}
  {rotate position by degrees}
\macrodef{rot\_}{rot_}{({\sl x, y, angle})}
  {gen}
  {rotate {\sl x,y} by theta radians}
\macrodef{rotbox}{rotbox}{({\sl wid,ht,type},[r|t={\sl val}])}
  {gen}
  {box oriented in current direction in {\tt [ ]} block;
   {\sl type}= e.g. {\tt dotted shaded "green".}  Defined internal
   locations: N, E, S, W (and NE, SE, NW, SW if arg4 is blank).  If arg4
   is {\tt r=}{\sl val} then corners have radius {\sl val}.  If arg4 is
   {\tt t=}{\sl val} then a spline with tension {\sl val} is used to draw
   a ``superellipse,'' and the bounding box is then only approximate. }
\macrodef{rotellipse}{rotellipse}{({\sl wid,ht,attributes})}
  {gen}
  {ellipse oriented in current direction in {\tt [ ]} block;
   e.g. {\tt Point\_(45); rotellipse(,{},dotted fill\_(0.9)).} Defined
   internal locations: N, S, E, W.}
\macrodef{round}{round}{(at {\sl location,line thickness,attributes})}
  {gen}
  {filled circle for rounded corners; attributes={\tt colored
  "gray"}
   for example; leaves {\tt Here} unchanged if arg1 is blank
    \seesect{Corners:}}
\macrodef{rpoint\_}{rpoint_}{(\linespec)}
  {gen}
  {set direction cosines}
\macrodef{rpos\_}{rpos_}{({\sl position})}
  {gen}
  {Here + {\sl position}}
\macrodef{rrot\_}{rrot_}{({\sl x, y, angle})}
  {gen}
  {\tt Here + vrot\_({\sl x, y, cos(angle), sin(angle))}}
\macrodef{rs\_box}{rs_box}{([angle={\sl degrees};]
     {\sl text},{\sl expr1},$\cdots$)}
  {gen}
  {like {\tt s\_box} but the text is rotated by {\tt text\_ang}
   (default 90) degrees, unless
   the first argument begins with {\tt angle={\sl decimal number};},
   in which case the number defines the rotation angle.
   Two or more args are passed to {\tt sprintf()}.
   If the first argument begins with {\tt angle={\sl expr};} then
   the specified angle is used.
   The examples {\tt define(`text\_ang',45); rs\_box(Hello World)} and
   {\tt rs\_box(angle=45; Hello World)} are equivalent
   \seesect{Interaction:}, \seesect{Pstricks:}}
\macrodef{rsvec\_}{rsvec_}{({\sl position})}
  {gen}
  {Here + {\sl position}}
\macrodef{rt\_}{rt_}{}
  {gen}
  {right with respect to current direction}
\macrodef{rtod\_\_}{rtod__}{}
  {gen}
  {constant, degrees/radian}
\macrodef{rtod\_}{rtod_}{}
  {gen}
  {constant, degrees/radian}
\macrodef{rvec\_}{rvec_}{({\sl x},{\sl y})}
  {gen}
  {location relative to current direction}
\Letter{S}%
\macrodef{s\_}{s_}{}
  {gen}
  {.s with respect to current direction}
\macrodef{s\_box}{s_box}{({\sl text},{\sl expr1},$\cdots$)}
  {gen}
  {generate dimensioned text string using {\tt\char92{}boxdims} from
    {\tt boxdims.sty}. Two or more args are passed to {\tt sprintf()}
   (default 90) degrees \seesect{Interaction:}}
\macrodef{s\_dp}{s_dp}{({\sl name},{\sl default})}
  {gen}
  {depth of the most recent (or named) {\tt s\_box}
    \seesect{Interaction:}}
\macrodef{s\_ht}{s_ht}{({\sl name},{\sl default})}
  {gen}
  {height of the most recent (or named) {\tt s\_box}
    \seesect{Interaction:}}
\macrodef{s\_init}{s_init}{({\sl name})}
  {gen}
  {initialize {\tt s\_box} string label to {\sl name} which should
  be unique
    \seesect{Interaction:}}
\macrodef{s\_name}{s_name}{}
  {gen}
  {the value of the last {\tt s\_init} argument
    \seesect{Interaction:}}
\macrodef{s\_wd}{s_wd}{({\sl name},{\sl default})}
  {gen}
  {width of the most recent (or named) {\tt s\_box}
    \seesect{Interaction:}}
\macrodef{sarrow}{sarrow}{(\linespec,{\sl keys})}
  {gen}
  {Single-segment, single-headed special arrows.
    The {\sl keys} are
       {\tt type=}{\tt O[pen]} (default)
          | {\tt D[iamond]} | {\tt C[rowfoot]} | {\tt P[lain]}{\tt ;}
       {\tt wdth=}{\tt expression}{\tt ;} (default {\tt arrowwid})
       {\tt lgth=}{\tt expression}{\tt ;} (default {\tt arrowht})
       {\tt shaft=}{\sl shaft attributes} (e.g., {\tt dashed}){\tt ;}
       {\tt head=}{\sl head attributes} (e.g., {\tt shaded}){\tt ;}
  \seesect{Macroarguments:}}
\macrodef{savem4dir}{savem4dir}{([`{\sl stack name}'])}
  {gen}
  {Stack m4 direction parameters in the named stack
    (default {\tt `savm4dir\_'})}
\macrodef{sbs}{sbs}{({\sl linespec, chars, label})}
  {cct}
  {Wrapper to place an SBS thyristor as a two-terminal element with
   {\tt [ ]} block label given by the third argument
    \seesect{Semiconductors:}}
\macrodef{sc\_draw}{sc_draw}{({\sl dna string, chars, iftrue, iffalse})}
  {cct}
  {test if chars are in string, deleting chars from string}
\macrodef{scr}{scr}{({\sl linespec, chars, label})}
  {cct}
  {Wrapper to place an SCR thyristor as a two-terminal element with
   {\tt [ ]} block label given by the third argument
    \seesect{Semiconductors:}}
\macrodef{scs}{scs}{({\sl linespec, chars, label})}
  {cct}
  {Wrapper to place an SCS thyristor as a two-terminal element with
   {\tt [ ]} block label given by the third argument
    \seesect{Semiconductors:}}
\macrodef{se\_}{se_}{}
  {gen}
  {.se with respect to current direction}
\macrodef{series\_}{series_}{({\sl elementspec}, {\sl elementspec},
$\ldots$)}
  {cct}
  { Series combination in a {\tt []} block of elements
    with shortened default length.  An {\sl elementspec} is of the
    form {\tt [{\sl Label}:] {\sl element}; [{\sl attributes}]},
    where an {\sl attribute} is of the form {\tt [llabel($\ldots$);] |
    [rlabel($\ldots$);] [b\_current($\ldots$);]}.  Internal points {\tt
    Start}, {\tt End}, and {\tt C} are defined
   \seesect{Seriesandparallel:} }
\macrodef{setdir\_}{setdir_}{(R|L|U|D|{\sl degrees}, {\sl default}
    U|D|R|L|{\sl degrees})}
  {gen}
  {store drawing direction and set it to
    up, down, left, right, or angle in degrees (reset by {\tt
    resetdir\_}).  The directions may be spelled out, i.e., Right,
    Left, $\ldots$
   \seesect{Seriesandparallel:}}
\macrodef{setrgb}{setrgb}{({\sl red value, green value, blue value},[{\sl
   name}])}
  {gen}
  {define colour for lines and text, optionally named (default
   {\tt lcspec}); \seesect{Semiconductors:}}
\macrodef{setkey\_}{setkey_}{({\sl string, key, default,}[N])}
  {gen}
  {Key-value definition, like {\tt pushkey\_()} but the resulting
  macro is defined using {\tt define()} rather than {\tt pushdef().}
   \seesect{Macroarguments:}}
\macrodef{setkeys\_}{setkeys_}{({\sl string, key sequence})}
  {gen}
  {Multiple key-value definition using {\tt define()} rather than
   {\tt pushdef().} See macro {\tt pushkeys\_}.
   \seesect{Macroarguments:}}
\macrodef{setview}{setview}{({\sl azimuth degrees},{\sl elevation
degrees})}
  {3D} {set projection viewpoint}
\macrodef{sfg\_init}{sfg_init}{({\sl default line len, node rad,
arrowhd len,
  arrowhd wid}), (reads {\tt libcct.m4})} {cct}
  {initialization of signal
  flow graph macros}
\macrodef{sfgabove}{sfgabove}{}
  {cct}
  {like above but with extra space}
\macrodef{sfgarc}{sfgarc}{(\linespec,{\sl text},{\sl text
justification},cw|ccw,
    {\sl height scale factor})}
  {cct}
  {directed arc drawn between nodes, with text label
    and a height-adjustment parameter }
\macrodef{sfgbelow}{sfgbelow}{}
  {cct}
  {like below but with extra space}
\macrodef{sfgline}{sfgline}{(\linespec,{\sl text},{\sl text
justification})}
  {cct}
  {directed straight line chopped by node radius, with text label}
\macrodef{sfgnode}{sfgnode}{(at {\sl location},{\sl text},above|below,{\sl
   circle options})}
  {cct}
  {small circle default white interior, with text label. The default
  label position is inside if the diameter is bigger than {\tt textht}
  and {\tt textwid}; otherwise it is {\tt sfgabove.} Options such as
  fill or line thickness can be given.}
\macrodef{sfgself}{sfgself}{(at {\sl location}, U|D|L|R|{\sl degrees},
   {\sl text}, {\sl text justification}, cw|ccw, {\sl scale factor})}
  {cct}
  {self-loop drawn at angle {\sl angle} from a node,
     with text label and a size-adjustment parameter }
\macrodef{shade}{shade}{({\sl gray value},{\sl closed line specs})}
  {gen}
  {Fill arbitrary closed curve. Note: when producing pdf via pdflatex, line
   thickness changes within this macro must be made via the {\tt linethick}
   environment variable rather than by the {\tt thickness} line attribute}
\macrodef{shadebox}{shadebox}{(box {\sl attributes, shade width})}
  {gen}
  {Box with edge shading.  Arg2 is in points. See also {\tt shaded} }
\macrodef{ShadedPolygon}{ShadedPolygon}{({\sl vertexseq, line attributes,
  degrees, colorseq})} {gen}
  {Draws the polygon specified in arg1 and
  shades the interior according
   to arg4 by drawing lines perpendicular to the angle in arg3.  The {\sl
   vertexseq} is a colon ({\tt:}) separated sequence of vertex positions
   (or names) of the polygon in cw or ccw order. A {\sl colorseq} is of
   the form 0, r0,g0,b0, {\sl frac1},r1,g1,b1, {\sl frac2},r2,g2,b2,
   \ldots 1,rn,gn,bn with $0 < \hbox{\sl frac1} < \hbox{\sl frac2}
   \ldots 1$ }
\macrodef{shadowed}{shadowed}{(box|circle|ellipse|line,
  {\sl position spec, keys})}
  {gen}
  { Object with specified shadow.  {\sl possspec} is e.g.,
    {\tt with .w at ...} or {\tt at} {\sl position}.
    The {\sl keys} are
       {\tt attrib=}{\sl object attributes}{\tt ;}
       {\tt shadowthick=}{\sl expr}{\tt ;} (default {\tt linethick*)}5/4),
       {\tt shadowcolor=}{\sl string}{\tt ;} (default {\tt "gray"}),
       {\tt shadowangle=}{\sl expr}{\tt ;} (default $-45$)
       for box only: {\tt rad=}{\sl expr}{\tt ;}
 }
\macrodef{shielded}{shielded}{(`{\sl two-terminal element}',
  L|U, {\sl line attributes})} {cct}
  {shielding in a {\tt [ ]} box for
  two-terminal element. Arg2= blank
    (default) to enclose the element body; L for the left side with
    respect to drawing direction, R for right. Internal points {\tt
    .Start, .End,} and {\tt .C} are defined}
\macrodef{SIdefaults}{SIdefaults}{}
  {gen}
  {Sets {\tt scale = 25.4} for drawing units in mm, and sets
   pic parameters {\tt lineht = 12, linewid = 12, moveht = 12,
    movewid = 12,
    arcrad = 6, circlerad = 6, boxht = 12, boxwid = 18, ellipseht = 12,
    ellipsewid = 18, dashwid = 2, arrowht = 3, arrowwid = arrowht/2,}}
\macrodef{sign\_}{sign_}{({\sl number})}
  {gen}
  {sign function}
\macrodef{Sin}{Sin}{({\sl integer})}
  {gen}
  {sine function, {\sl integer\/} degrees}
\macrodef{sinc}{sinc}{({\sl number})}
  {gen}
  {the $\hbox{sinc}(x)$ function}
\macrodef{sind}{sind}{({\sl arg})}
  {gen}
  {sine of an expression in degrees}
\macrodef{sinusoid}{sinusoid}{({\sl amplitude, frequency, phase, tmin,
  tmax, linetype})}
  {gen}
  {draws a sinusoid over the interval $(t_{\hbox{\scriptsize min}},
  t_{\hbox{\scriptsize max}})$;
   e.g., to draw a dashed sine curve, amplitude {\sl a},
   of {\sl n} cycles of length {\sl x} from {\sl A}, {\tt
   sinusoid(a,twopi\_*n/x,-pi\_/2,0,x,dashed) with .Start at A}}
\macrodef{sl\_box}{sl_box}{({\sl stem linespec, keys, stem object})}
  {SLD}
  {One-terminal SLD element: argument 1 is a \linespec\ to define the stem
   or, in the case of a zero-length stem, one of {\tt U, D, L, R,} or an
   angle in degrees, optionally followed by {\tt at {\sl position}}.
   The position is {\sl Here} by default.

   Argument 2 contains semicolon (;)-separated key-value attributes
   of the head:
   {\tt name={\sl{}Name}} (default {\sl Head});
   {\tt lgth={\sl{}expr}};
   {\tt wdth={\sl{}expr}};
   {\tt text="{\sl{}text}"},
   {\tt box={\sl{}box pic attributes}}.

   If argument 3 is null then a plain stem is drawn; if it is of the
   form {\tt S:}{\sl keys} or {\tt S$n$:}{\sl keys} an $n$-line slash
   symbol is overlaid on the stem; otherwise the keys are for an overlaid
   breaker, so that a {\tt C} specifies a default closed breaker, {\tt
   O} an open breaker, {\tt X,} {\tt /,} or \bsl\ for these marks, or
   \MR{sl_ttbox}{\tt sl\_ttbox} key-value pairs defining box attributes
   for the breaker (default name {\sl Br})

   \seesect{SingleLine:}}
\macrodef{sl\_breaker}{sl_breaker}{({\sl linespec,} {\tt type=[A|C][D];}
  {\sl ttbox args})}
  {SLD}
  {Two-terminal SLD element:
   type {\tt A} (the default) is for a box breaker; type 
   {\tt C} for a curved breaker; adding a {\tt D} puts drawout elements
   in the input and output leads.
   Otherwise, the arguments are as for 
   \MR{sl_ttbox}{\tt sl\_ttbox}
   \seesect{SingleLine:}}
\macrodef{sl\_busbar}{sl_busbar}{({\sl linespec, np, keys})}
  {SLD}
  {Composite SLD element drawn in a {\tt [ ]} block.  A busbar is
   essentially a thick straight line 
   drawn along the {\sl linespec} with positions evenly distributed
   along it.  For example,
     {\tt line right\_; sl\_busbar(, up\_ 4.5, 5) with .P3 at Here}.

   Argument 1 is a \linespec\ to define the direction and length of the
     busbar (but not its position, since it is drawn in a {\tt [ ]} block).

   Argument 2 is the number $np$ of evenly spaced positions
     $P1, P2, \ldots Pnp$ along the line with $P1$ and $Pnp$ indented
     from the ends of the line.

   Argument 3 contains semicolon (;)-separated key-value attributes
     of the line:
   {\tt port=D} (for a dot at each port position);
   {\tt line=}{\sl pic line attributes}.
   {\tt indent=}{\sl indent distance}.
   \seesect{SingleLine:}}
\macrodef{sl\_ct}{sl_ct}{%
    ({\tt at}{\sl position},{\sl keys},{\tt R|L|U|D|}{\sl degrees})}
  {SLD}
  {Composite SLD element drawn in a {\tt [ ]} block:

   The keys are as follows:
   {\tt type=L|N|S[n]} (default {\tt L;} {\tt S$n$} draws an $n$-line slash
     symbol, default 2); {\tt N} means no stem);
   {\tt scale={\sl expr} (default 1.0)};
   {\tt grnd={\sl expr} attached ground at given angle
     (type {\tt S} or {\tt N}))};
   {\tt sep={\sl{}expr}};
   {\tt stemlgth={\sl{}expr}};
   {\tt wdth={\sl{}expr}};
   {\tt direct=U|D|L|R|{\sl degrees}} (drawing direction).

   Key {\tt stemlgth} is the length of the leads at the start, centre, and end,
     with labeled ends {\sl Tstart, Tc,} and {\sl Tend}.
     The {\tt L} (default) variant also defines internal labels
     Internal labels {\sl L} and {\sl C} are included.

   Key {\tt sep} is the type-{\tt S} separation from the head to the centre
     of the slash symbol.

   Key {\tt scale} allows scaling (default scale 1.0) but, with \dpic,
     the {\tt scaled} directive can also be used.
   \seesect{SingleLine:}}
\macrodef{sl\_disk}{sl_disk}{({\sl stem linespec, keys, breaker})}
  {SLD}
  {One-terminal SLD element: argument 1 is a \linespec\ to define the stem
   or, in the case of a zero-length stem, one of {\tt U, D, L, R,} or an
   angle in degrees, optionally followed by {\tt at {\sl position}}.
   The position is {\sl Here} by default.

   Argument 2 contains semicolon (;)-separated key-value attributes
   of the head:
   {\tt name={\sl{}Name}} (default {\sl Head});
   {\tt text="{\sl{}text}"};
   {\tt diam={\sl{}expr}};
   {\tt circle={\sl{}circle pic attributes}}.

   Argument 3 is null for no breaker in the stem, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   \MR{sl_ttbox}{\tt sl\_ttbox}
   key-value pairs defining box attributes for the breaker
   (default name {\sl Br})
   \label{sl_disk}%
   \seesect{SingleLine:}}
\macrodef{sl\_drawout}{sl_drawout}{({\sl linespec, keys,} R)}
  {SLD}
  {Two-terminal SLD element: argument 1 is a \linespec\ as for ordinary
   two-terminal elements.

   Argument 2 contains semicolon (;)-separated key-value body attributes:
   {\tt type=T} (for truncated leads);
   {\tt lgth={\sl{}expr},}
   {\tt wdth={\sl{}expr}} (body size);
   {\tt name={\sl{}Name}} (default {\sl Body});
   {\tt line={\sl{}pic line attributes}}; (e.g., {\tt thick 2})

   Argument 3 is {\tt R} to reverse the direction of the drawn chevrons.
   \seesect{SingleLine:}}
\macrodef{sl\_generator}{sl_generator}{({\sl stem linespec, keys, breaker})}
  {SLD}
  {One-terminal SLD element: argument 2 is
   {\tt type=AC|WT|BS|StatG|PV|Y|Delta} and,
   if {\tt type=PV,} the {\tt SL\_box} keys;
   otherwise, the {\tt sl\_disk} body keys.

   Argument 3 is null for no breaker in the stem, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   \MR{sl_ttbox}{\tt sl\_ttbox}
   key-value pairs defining box attributes for the breaker
   (default name {\sl Br})
   \seesect{SingleLine:}}
\macrodef{sl\_grid}{sl_grid}{({\sl stem linespec, keys, breaker})}
  {SLD}
  {One-terminal SLD element: argument 1 is a \linespec\ to define the stem
   or, in the case of a zero-length stem, one of {\tt U, D, L, R,} or an
   angle in degrees, optionally followed by {\tt at {\sl position}}.
   The position is {\sl Here} by default.

   Argument 2 contains semicolon (;)-separated key-value attributes
   of the head:
   {\tt name={\sl{}Name}} (default {\sl Head});
   {\tt lgth={\sl{}expr}};
   {\tt wdth={\sl{}expr}}.

   Argument 3 is null for no breaker in the stem, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   \MR{sl_ttbox}{\tt sl\_ttbox}
   key-value pairs defining box attributes for the breaker
   (default name {\sl Br})
   \seesect{SingleLine:}}
\macrodef{sl\_inverter}{sl_inverter}{({\sl ttbox args})}
  {SLD}
  {Two-terminal SLD element: the arguments are as for 
   \MR{sl_ttbox}{\tt sl\_ttbox}
   \seesect{SingleLine:}}
\macrodef{sl\_lamp}{sl_lamp}{({\sl stem linespec, keys, breaker})}
  {SLD}
  {One-terminal SLD element: the arguments are as for 
   \MR{sl_disk}{\tt sl\_disk}
   \seesect{SingleLine:}}
\macrodef{sl\_load}{sl_load}{({\sl stem linespec, keys, breaker})}
  {SLD}
  {One-terminal SLD element: argument 1 is a \linespec\ to define the stem
   or, in the case of a zero-length stem, one of {\tt U, D, L, R,} or an
   angle in degrees, optionally followed by {\tt at {\sl position}}.
   The position is {\sl Here} by default.

   Argument 2 contains semicolon (;)-separated key-value attributes
   of the head:
   {\tt name={\sl{}Name}} (default {\sl Head});
   {\tt lgth={\sl{}expr}};
   {\tt wdth={\sl{}expr}};
   {\tt head={\sl{}arrowhead pic attributes}}.

   Argument 3 is null for no breaker in the stem, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   \MR{sl_ttbox}{\tt sl\_ttbox}
   key-value pairs defining box attributes for the breaker
   (default name {\sl Br})
   \seesect{SingleLine:}}
\macrodef{sl\_meterbox}{sl_meterbox}{({\sl stem linespec, keys, breaker})}
  {SLD}
  {One-terminal SLD element: argument 1 is a \linespec\ to define the stem
   or, in the case of a zero-length stem, one of {\tt U, D, L, R,} or an
   angle in degrees, optionally followed by {\tt at {\sl position}}.
   The position is {\sl Here} by default.

   Argument 2 contains semicolon (;)-separated key-value attributes
   of the head:
   {\tt name={\sl{}Name}} (default {\sl Head});
   {\tt lgth={\sl{}expr}};
   {\tt wdth={\sl{}expr}};
   {\tt text="{\sl{}text}"},
   {\tt box={\sl{}box pic attributes}}.

   Argument 3 is null for no breaker in the stem, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   \MR{sl_ttbox}{\tt sl\_ttbox}
   key-value pairs defining box attributes for the breaker
   (default name {\sl Br})
   \seesect{SingleLine:}}
\macrodef{sl\_reactor}{sl_reactor}{({\sl stem linespec, keys, breaker keys,
    breaker keys})}
  {SLD}
  {Two-terminal SLD element: argument 1 is a \linespec\ as for ordinary
   two-terminal elements.

   Argument 2 contains semicolon (;)-separated key-value body attributes:
   {\tt name={\sl{}Name}} (default {\sl Body});
   {\tt diam={\sl{}expr}}.

   Argument 3 is null for no breaker in the input lead, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   key-value pairs as above defining breaker attributes
   except that the default breaker name is {\sl BrI}.

   Argument 4 defines the breaker in the output lead as for argument 3
   except that the default breaker name is {\sl BrO}.
   \seesect{SingleLine:}}
\macrodef{sl\_rectifier}{sl_rectifier}{({\sl ttbox args})}
  {SLD}
  {Two-terminal SLD element: the arguments are as for 
   \MR{sl_ttbox}{\tt sl\_ttbox}
   \seesect{SingleLine:}}
\macrodef{sl\_slash}{sl_slash}{(at {\sl position, keys,}
   [$n$:]R|L|U|D|{\sl degrees})}
  {SLD}
  {Slash symbol for SLD elements: draws $n$ slashes in a {\tt [] } block.
   The keys are
   {\tt lines={\sl line attributes,} e.g., dotted thick {\sl expr}};
   {\tt size=}{\sl expr} (default {\tt ht dimen\_/3}).
   \seesect{SingleLine:}}
%
\macrodef{sl\_transformer}{sl_transformer}{({\sl linespec, keys,
    input breaker keys, output breaker keys,
    input circle inner object, output circle inner object})}
  {SLD}
  {Two-terminal SLD element: argument 1 is a \linespec\ as for ordinary
   two-terminal elements.

   Argument 2 contains semicolon (;)-separated key-value body attributes:
   {\tt name={\sl{}Name}} (default {\sl Body});
   {\tt scale={\sl expr}} (body size factor, default 1.0);
   {\tt type=I|S|A[R]} (default {\tt I}).

   Additional type {\tt I} keys are
   {\tt cycles={\sl{}integer}} (default 4);
   {\tt core=A|M[$n$]|P[$n$]|K[$n$]}, $n$={\sl integer} (default 2 lines).

   Additional type {\tt S} keys are
   {\tt body={\sl circle pic attributes}} e.g., {\tt shaded "{\sl color}"}.

   Type {\tt A} keys are
   {\tt body={\sl circle pic attributes}}.  Type {\tt AR} means right
   orientation.

   Argument 3 is null for no breaker in the input lead, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   key-value pairs as above defining breaker attributes
   except that the default breaker name is {\sl BrI}.

   Argument 4 defines the breaker in the output lead as for argument 3
   except that the default breaker name is {\sl BrO}.

   Argumentss 5 and 6 for the input and output circles respectively are:
   {\tt Y} for a Y-symbol;
   {\tt YN} for a Y-symbol with ground;
   {\tt Delta} for a $\Delta$ symbol;
   otherwise, other customization commands expanded in a {\tt \lbr\rbr} pair.
   \seesect{SingleLine:}}
%
\macrodef{sl\_transformer3}{sl_transformer3}{({\sl linespec, keys,
    breaker keys, symbol keys})}
  {SLD}
  {Composite (block) SLD element: argument 1 is a \linespec\ that can be used
   to set the direction and distance between primary terminals but not
   position.

   Argument 2 contains semicolon (;)-separated key-value body attributes:
   {\tt name={\sl{}Name}} (default {\sl Body});
   {\tt type=S|C} (default {\tt S});
   {\tt scale={\sl expr}} (body size factor, default 1.0);
   {\tt direct=L|R} (default {\tt L}) direction of the tertiary
     circle and terminal relative to the drawing direction;
   {\tt body={\sl circle attributes}}.

   Argument 3 is colon (:)-separated sequence of up to three breaker
   attribute specifications for the input, output, and teriary breaker
   in order.  A null or blank means no breaker, {\tt tt\_breaker}
   specifications otherwise. Default breaker names are {\sl BrI}
   and {\sl BrO} as for
   {\tt sl\_transformer,} and {\sl Br} for the third breaker. 

   Argument 4 is colon (:)-separated sequence of up to three symbol
   specifications for the input, output, and teriary circle
   in order.  A null or blank means no symbol;
   {\tt Y} for a Y-symbol;
   {\tt Delta} for a $\Delta$ symbol;
   otherwise, other customization commands expanded in a {\tt \lbr\rbr} pair.
   \seesect{SingleLine:}}
\macrodef{sl\_ttbox}{sl_ttbox}{({\sl linespec, keys, input breaker keys,
    output breaker keys})}
  {SLD}
  {Two-terminal SLD element: argument 1 is a \linespec\ as for ordinary
   two-terminal elements.

   Argument 2 contains semicolon (;)-separated key-value body attributes:
   {\tt name={\sl{}Name}} (default {\sl Body});
   {\tt lgth={\sl{}expr}};
   {\tt wdth={\sl{}expr}};
   {\tt text="{\sl{}text}"};
   {\tt box={\sl{}box pic attributes}};
   {\tt supp={\sl{}additional {\tt rotbox} commands}}.

   Argument 3 is null for no breaker in the input lead, {\tt C} for a default
   closed breaker, {\tt O} for an open breaker, {\tt X,} {\tt /,} or \bsl\ for
   these marks, or
   key-value pairs as above defining breaker attributes
   except that the default breaker name is {\sl BrI}.

   Argument 4 defines the breaker in the output lead as for argument 3
   except that the default breaker name is {\sl BrO}.
   \label{sl_ttbox}%
   \seesect{SingleLine:}}
\macrodef{source}{source}{(\linespec,
   V|v|I|i|AC|B|F|G|H|J|Q|L|N|P|S[C[r]]|E[r]]|T|X|U|{\sl other}, {\sl
   diameter},R)}
  {cct}
  {source, blank or:
                     V = voltage source; v = alternate voltage source; I =
                     current source; i = alternate current source; AC =
                     AC source; B = bulb; F = fluorescent; G = generator;
                     H = step function; L = lamp; N = neon; P = pulse;
                     Q = charge; R = ramp; r = right orientation; S =
                     sinusoid; SC = quarter arc; SE = arc; T = triangle;
                     U = square-wave; X = interior X; other = custom
                     interior label or waveform; arg 4: R = reversed
                     polarity; arg 5 modifies the circle with e.g.,
                     color or fill
   \seesect{Twoterminal:}}
\macrodef{sourcerad\_}{sourcerad_}{}
  {cct}
  {default source radius}
\macrodef{sp\_}{sp_}{}
  {gen}
  {evaluates to medium space for gpic strings}
\macrodef{speaker}{speaker}{( U|D|L|R|{\sl degrees},{\sl size},H)}
  {cct}
  {speaker, {\sl In1} to {\sl In7} defined; {\tt H}=horn
   \seesect{Composite:}}
\macrodef{sprod3D}{sprod3D}{(a,x,y,z)}
  {3D} {scalar product of triple x,y,z by a}
\macrodef{sqrta}{sqrta}{({\sl arg})}
  {gen}
  {square root of the absolute value of {\sl arg}; i.e.,
   {\tt sqrt(abs({\sl arg}))}}
\macrodef{SQUID}{SQUID}{({\sl n, diameter, initial angle}, {\tt ccw|cw})}
  {cct}
  {Superconducting quantum interface device
   with {\sl }n junctions labeled {\tt J1, ... J}{\sl n} placed around
   a circle with initial angle -90 deg (by default) with respect to the
   current drawing direction. The default diameter is {\tt dimen\_} }
\macrodef{stackargs\_}{stackargs}{(`{\sl stackname}',{\sl args})}
  {gen}
  {Stack arg 2, arg 3, ... onto the named stack up to a blank arg}
\macrodef{stackcopy\_}{stackcopy_}{(`{\sl name 1}',`{\sl name 2}')}
  {gen}
  {Copy stack 1 into stack 2, preserving the order of pushed
  elements}
\macrodef{stackdo\_}{stackdo}{(`{\sl stackname}',{\sl commands})}
  {gen}
  {Empty the stack to the first blank entry, performing arg 2}
\macrodef{stackexec\_}{stackexec_}{(`{\sl name 1}',`{\sl name 2}',%
 {\sl commands})}
  {gen}
  {Copy stack 1 into stack 2, performing arg3 for each nonblank
  entry}
\macrodef{stackprint\_}{stackprint_}{(`{\sl stack name}')}
  {gen}
  {Print the contents of the stack to the terminal}
%\macrodef{stackpromote\_}{stackpromote_}{({\sl prefix},% 
% `{\sl stack name}',{\sl In name})}
%  {gen}
%  {Define locations {\tt In1} or {\sl In name }{\tt 1}, $\ldots$ corresponding %   to the locations in stack {\sl stack name}, as created by the
%   {\tt AutoGate} and {\tt Autologic} macros.  Each location is prefixed
%   by argument 1 ``.''}
\macrodef{stackreverse\_}{stackreverse_}{(`{\sl stack name}')}
  {gen}
  {Reverse the order of elements in a stack, preserving the name}
\macrodef{stacksplit\_}{stacksplit_}{(`{\sl stack name}',{\sl string},{\sl
   separator})}
  {gen}
  {Stack the fields of {\sl string} left to right separated
  by nonblank
    {\sl separator} (default .).  White space preceding the fields
    is ignored.}
\macrodef{sum\_}{sum_}{({\sl a},{\sl b})}
  {gen}
  {binary sum}
\macrodef{sum3D}{sum3D}{({\sl x1,y1,z1,x2,y2,z2})}
  {3D} {sum of two triples}
\macrodef{sus}{sus}{({\sl linespec, chars, label})}
  {cct}
  {Wrapper to place an SUS thyristor as a two-terminal element with
   {\tt [ ]} block label given by the third argument
    \seesect{Semiconductors:}}
\macrodef{svec\_}{svec_}{({\sl x},{\sl y})}
  {log}
  {scaled and rotated grid coordinate vector}
\macrodef{sw\_}{sw_}{}
  {gen}
  {.sw with respect to current direction}
\macrodef{switch}{switch}{(\linespec,L|R,[C|O][D],[B|D])}
  {cct}
  {SPST switch (wrapper for bswitch, lswitch, and dswitch),
    arg2: R=right orientation (default L=left);
     if arg4=blank (knife switch): arg3 = [O{\tt|}C][D][A]
       O= opening, C=closing, D=dots, A=blade arrowhead;
     if arg4=B (button switch): arg3 = O{\tt|}C
       O=normally open, C=normally closed,
     if arg4=D: arg3 = same as for dswitch \seesect{Twoterminal:}}
\Letter{T}%
\macrodef{ta\_xy}{ta_xy}{({\sl x, y})}
  {cct}
  {macro-internal coordinates adjusted for {\tt L|R}}
\macrodef{tapped}{tapped}{(`{\sl two-terminal element}',
  [{\sl arrowhd} | type={\sl arrowhd};name={\sl Name}],
    {\sl fraction, length, fraction, length,} $\cdots$)}
  {cct}
  {Draw the two-terminal element with taps in a [ ] block (see
  {\tt addtaps}).
   {\sl arrowhd} = blank or one of {\tt . - <- -> <->}.  Each fraction
   determines the position along the element body of the tap.  A negative
   length draws the tap to the right of the current direction; positive
   length to the left.  Tap names are Tap1, Tap2, $\cdots$ by default
   or Name1, Name2, $\cdots$ if specified.  Internal block names are
   {\tt .Start, .End,} and {.C} corresponding to the drawn element,
   and the tap names \seesect{Composite:} }
\macrodef{tbox}{tbox}{({\sl text,wid,ht},<|>|<>,{\sl type})}
  {cct}
  {Pointed terminal box. The {\sl text} is placed at the rectangular
  center
   in math mode unless the text begins with {\tt "} or {\tt sprintf} in
   which case the arument is used literally.  Arg 4 determines whether
   the point is forward, backward, or both with respect to the current
   drawing direction.
    \seesect{Composite:}}
\macrodef{tconn}{tconn}{({\sl linespec, chars}|{\sl keys}, {\sl wid})}
  {cct}
  {Terminal connector drawn on a linespec, with head enclosed in a {\tt [ ]}
   block.  The permissible {\sl chars} are:
   {\tt > | >> | < | << | A | AA | M | O | OF}.
   Type {\tt O} draws a node (circle); {\tt OF} a filled circle.
   Type {\tt M} is a black bar; {\tt A} is an open arc end; type {\tt AA}
   a double open arc.  Type {\tt >} (the default) is an arrow-like output
   connector; {\tt <} and {\tt <<} input connectors.  Arg 3 is arrowhead
   width or circle diameter when key-value pairs are not used.
   If keys are specified, they are {\tt type=}{\sl chars} as previously;
   {\tt wdth=}{\sl expr}; {\tt lgth=}{\sl expr}; {\tt sep=}{\sl expr};
   {\tt head=}{\sl attributes except} {\tt lgth, wdth.}
   The key {\tt sep=} is the double-head separation
    \seesect{Composite:}}
\macrodef{tgate}{tgate}{({\sl linespec,} [B][R|L])}
  {cct}
  {transmission gate, {\tt B=} ebox type; {\tt L=} oriented left
    \seesect{Semiconductors:}}
\macrodef{thermocouple}{thermocouple}{({\sl linespec, wid, ht,} L|R [T])}
  {cct}
  { Thermocouple drawn to the left (by default) of the
    {\sl linespec} line.  A {\tt T} argument truncates the leads so
    only the two branches appear.  {\tt R=}
    right orientation.  \seesect{Twoterminal:}}
\macrodef{thicklines\_}{thicklines_}{({\sl number})}
  {gen}
  {set line thickness in points}
\macrodef{thinlines\_}{thinlines_}{({\sl number})}
  {gen}
  {set line thickness in points}
\macrodef{threeD\_init}{threeD_init}{}
  {3D} {initialize 3D transformations (reads {\tt lib3D.m4})}
\macrodef{thyristor}{thyristor}{(\linespec,%
 {\tt [SCR|SCS|SUS|SBS|IEC][{\sl chars}]})}
  {cct}
  {Composite thyristor element in {\tt []}block:
   types
                                   SCR: silicon controlled rectifier
                                   (default), SCS: silicon controlled
                                   switch, SUS: silicon unilateral switch,
                                   SBS: silicon bilateral switch, IEC:
                                   type IEC.
   {\sl Chars} to modify or define the element:
                                   K: open arrowheads, A: arrowhead, F:
                                   half arrowhead, B: bidirectional diode,
                                   E: adds envelope, H: perpendicular
                                   gate (endpoint G), N: anode gate
                                   (endpoint Ga), U: centre line in diodes
                                 V: perpendicular gate across arrowhead
                                 centre,
                                   R=right orientation, E=envelope
    \seesect{Semiconductors:}}
\macrodef{thyristor\_t}{thyristor_t}{({\sl linespec, chars, label})}
  {cct}
  {Wrapper to place a thyristor as a two-terminal element with
   {\tt [ ]} block label given by the third argument
    \seesect{Semiconductors:}}
\macrodef{tikznode}{tikznode}{({\sl \Tikz node name, position}) }
  {pgf}
  {insert \Tikz code to define a zero-size \Tikz node at {\sl location}
    (default {\tt Here}) to assist with inclusion of \pic code output
    in \Tikz diagrams.  This macro must be invoked in the outermost
    \pic scope.  \seesect{Tikzwithpic:}}
\macrodef{tline}{tline}{(\linespec,{\sl wid},{\sl ht}) }
  {cct}
  {transmission line, manhattan direction\seesect{Twoterminal:}}
\macrodef{ToPos}{ToPos}{({\sl position}, U|D|L|R|{\sl degrees}, {\sl length}) }
  {gen}
  {Evaluates to {\tt from {\sl position} - Rect\_({\sl length, angle}) to
   {\sl position}} from the polar-coordinate data in the arguments }
\macrodef{tr\_xy\_init}{tr_xy_init}{({\sl origin, unit size, sign })}
  {cct}
  {initialize {\tt tr\_xy}}
\macrodef{tr\_xy}{tr_xy}{({\sl x, y})}
  {cct}
  {relative macro internal coordinates adjusted for {\tt L|R}}
\macrodef{transformer}{transformer}{(\linespec,L|R,{\sl np},%
[A|P][W|L][D1|D2|D12|D21],{\sl ns})}
  {cct}
  {2-winding transformer or choke with terminals P1, P2, TP, S1,
  S2, TS:
    arg2: L = left, R = right, arg3: np primary arcs, arg5: ns secondary
    arcs, arg4: A = air core, P = powder (dashed) core, W = wide windings,
    L = looped windings, D1: phase dots at P1 and S1 end; D2 at P2 and
    S2 end; D12 at P1 and S2 end; D21 at P2 and S1 end
   \seesect{Composite:}}
\macrodef{tstrip}{tstrip}{(R|L|U|D|{\sl degrees, nterms, chars})}
  {cct}
  {terminal strip, chars:
   I=invisible terminals, C=circle terminals (default), D=dot terminals,
   O=omitted separator lines, {\tt wid=}value{\tt ;} total strip width,
   {\tt ht=}value{\tt ;} strip height
    \seesect{Composite:}}
\macrodef{ttmotor}{ttmotor}{({\sl linespec, string, diameter, brushwid,
brushht})}
  {cct}
  {motor with label\seesect{Twoterminal:}}
\macrodef{twopi\_}{twopi_}{}
  {gen}
  {$2\pi$}
\Letter{U}%
\macrodef{ujt}{ujt}{(\linespec,R,P,E)}
  {cct}
  {unijunction transistor, right, P-channel, envelope
    \seesect{Semiconductors:}}
\macrodef{unit3D}{unit3D}{(x,y,z)}
  {3D} {unit triple in the direction of triple x,y,z}
\macrodef{up\_\_}{up__}{}
  {gen}
  {up with respect to current direction}
\macrodef{up\_}{up_}{}
  {gen}
  {set current direction up \seesect{Placing:}}
\Letter{V}%
\macrodef{variable}{variable}{(`{\sl element}',
  {\tt [A|P|L|[u]N|[u]NN][C|S]}, [+|-]{\sl angle},
   {\sl length}, at position)}
  {cct}
  {overlaid arrow or line to indicate variable 2-terminal element:
    {\tt A}=arrow, {\tt P}=preset, {\tt L}=linear, {\tt N}= symmetric
    nonlinear, {\tt C}=continuous, {\tt S}=setpwise; {\tt u} changes
    the nonlinearity direction.  The angle is absolute but preceding
    it with a sign makes the angle (often -30 or -45) relative to the
    element drawing direction.  If arg5 is blank the symbol is placed
    over the last {\tt [ ]} block
   \seesect{Twoterminal:}}
\macrodef{Vcoords\_}{Vcoords_}{({\sl position})}
  {gen}
  {The $x, y$ coordinate pair of the position}
\macrodef{Vdiff\_}{Vdiff_}{({\sl position},{\sl position})}
  {gen}
  {{\tt Vdiff\_(A,B)} evaluates to {\tt A-(B)} with dpic, {\tt
  A-(B.x,B.y)}
   with gpic}
\macrodef{vec\_}{vec_}{({\sl x},{\sl y})}
  {gen}
  {position rotated with respect to current direction}
\macrodef{View3D}{View3D}{}
  {3D} {The view vector (triple) defined by {\tt setview({\sl azim,
  elev})}. The
   {\tt project} macro projects onto the plane perpendicular to this
   vector}
\macrodef{vlength}{vlength}{({\sl x},{\sl y})}
  {gen}
  {vector length $\sqrt{x^2+y^2}$}
\macrodef{vperp}{vperp}{({\sl linear object})}
  {gen}
  {unit-vector pair CCW-perpendicular to linear object}
\macrodef{Vperp}{Vperp}{({\sl position name}, {\sl position name})}
  {gen}
  {unit-vector pair CCW-perpendicular to line joining two named
  positions}
\macrodef{vrot\_}{vrot_}{({\sl x},{\sl y},{\sl xcosine},{\sl ycosine})}
  {gen}
  {rotation operator}
\macrodef{vscal\_}{vscal_}{({\sl number},{\sl x},{\sl y})}
  {gen}
  {vector scale operator}
\macrodef{Vsprod\_}{Vsprod_}{({\sl position}, {\sl expression})}
  {gen}
  {The vector in arg 1 multiplied by the scalar in arg 2}
\macrodef{Vsum\_}{Vsum_}{({\sl position},{\sl position})}
  {gen}
  {{\tt Vsum\_(A,B)} evaluates to {\tt A+B} with dpic, {\tt
  A+(B.x,B.y)}
   with gpic}
\Letter{W}%
\macrodef{w\_}{w_}{}
  {gen}
  {.w with respect to current direction}
\macrodef{while\_}{while_}{(`{\sl test}',`{\sl actions}')}
  {gen}
  {Integer m4 while loop}
\macrodef{wid\_}{wid_}{}
  {gen}
  {width with respect to current direction}
\macrodef{winding}{winding}{(L|R, {\sl diam, pitch, turns, core wid,
   core color})}
  {cct}
  {core winding drawn in the current direction; {\tt R}=right-handed
   \seesect{Composite:}}
\macrodef{XOR\_gate}{XOR_gate}{({\sl n},N)}
  {log}
  {`xor' gate, 2 or {\sl n\/} inputs; N=negated input.
   Otherwise, arg1 can be a sequence of letters {\tt P|N} to define
   normal or negated inputs.
    \seesect{Logicgates:}}
\macrodef{XOR\_off}{XOR_off}{}
  {log}
  {XOR and NXOR offset of input face}
\Letter{X}%
\macrodef{xtal}{xtal}{(\linespec,{\sl keys})}
  {cct}
  {Quartz crystal. The {\sl keys} are
     {\tt type=N} (default) or {\tt R} (round);
            type {\tt N} keys:
              {\tt lgth=}{\sl expr} (body length);
              {\tt wdth=}{\sl expr} (body width);
              {\tt bxwd=}{\sl expr} (body inner box width);
              {\tt box=} box attributes ({\tt shaded} $\ldots$);
            type {\tt R} keys:
              {\tt outerdiam=}{\sl expr};
              {\tt innerdiam=}{\sl expr};
              {\tt outer=} outer circle attributes ({\tt dotted} $\ldots$);
              {\tt inner=} inner circle attributes ({\tt shaded} $\ldots$)%
\seesect{Twoterminal:}}
\macrodef{xtract}{xtract}{({\sl string, substr1, substr2, $\ldots$})}
  {gen}
  {returns substrings if present}
\Letter{Y}%
\macrodef{Ysymbol}{Ysymbol}{(at {\sl position},keys,
    U|D|L|R|{\sl degrees}) (default {\tt U} for up)}
  {cct}
  {Y symbol for power-system diagrams
   {\sl keys:} {\tt size={\sl expression}; type=G}}
%  \end{tabbing}