%%
%% file: ob-mathleading.sty
%%
%% written by Kangsoo Kim, 
%% part of kotex-oblivoir
%%
%% a supplementary package to oblivoir
%% set lineskips in multi-lined math environments
%% (amsmath required)
%%
%% v. 0.1alpha  : 2018/12/22
%% v. 0.0.1-pr2 : 2018/12/24
%% v. 0.0.1     : 2018/12/25
%% v. 0.1		: 2022/04/01	: <split> fixed.
%% v. 0.2	: 2023/02/26, maintenance
%%
\RequirePackage{expl3}
\ProvidesExplPackage
	{ob-mathleading}
	{2023/02/26}
	{v0.2}
	{adjust math leadings for oblivoir}

\@ifpackageloaded{amsmath}{}{\RequirePackage{amsmath}}
\RequirePackage{xparse}
\RequirePackage{etoolbox}
\RequirePackage{l3keys2e}

\keys_define:nn { obmathleading }
{
	default			.bool_set:N	= \l_defaultopt_bool,
	mathleading		.fp_set:N 	= \l_opt_mathleading_fp,
	exception		.clist_set:N = \g_opt_mlexception_clist,
	noallowdisplaybreaks	.bool_set:N = \g_noallowdispbreak_bool,
	badm		.bool_set:N = \opt_badm_bool
}

\keys_set:nn { obmathleading }
{
	default 	= true,
	mathleading	= 1.0,
	exception	= {},
	noallowdisplaybreaks = false,
	badm = false
}

\ProcessKeysOptions { obmathleading }

\scan_stop:

\bool_if:NTF \l_defaultopt_bool
{
	\tl_set:Nn \l_obml_stretch_tl { \fp_use:N \l_opt_mathleading_fp }
}
{
	\tl_set:No \l_obml_stretch_tl { \baselinestretch }
}

\NewDocumentCommand \obmathleading { m }
{
	\tl_set:Nn \l_obml_stretch_tl { #1 }
}

\NewDocumentEnvironment { obMathLeading } { O{1.0} }
{
	\obmathleading { #1 }
}
{
}

\cs_new:Npn \mathleading_set_default:nN #1 #2
{
	\clist_if_in:NnF \g_opt_mlexception_clist { #1 }
	{
    	\AtBeginEnvironment { #1 }
    	{
    		\linespread { #2 } \selectfont \ignorespaces
    	}
	}
}

\cs_new:Npn \splitleading_set_default:N #1
{
	\clist_if_in:NnF \g_opt_mlexception_clist { split }
	{
    	\patchcmd \gather@split
    	{ \spread@equation }
    	{ \linespread { #1 } \selectfont \spread@equation }
    	{ }
    	{ }
	}
}

\mathleading_set_default:nN { array    } \l_obml_stretch_tl
\mathleading_set_default:nN { matrix   } \l_obml_stretch_tl
\mathleading_set_default:nN { matrix*  } \l_obml_stretch_tl
\mathleading_set_default:nN { pmatrix  } \l_obml_stretch_tl
\mathleading_set_default:nN { pmatrix* } \l_obml_stretch_tl
\mathleading_set_default:nN { bmatrix  } \l_obml_stretch_tl
\mathleading_set_default:nN { bmatrix* } \l_obml_stretch_tl
\mathleading_set_default:nN { Bmatrix  } \l_obml_stretch_tl
\mathleading_set_default:nN { Bmatrix* } \l_obml_stretch_tl
\mathleading_set_default:nN { vmatrix  } \l_obml_stretch_tl
\mathleading_set_default:nN { vmatrix* } \l_obml_stretch_tl
\mathleading_set_default:nN { Vmatrix  } \l_obml_stretch_tl
\mathleading_set_default:nN { Vmatrix* } \l_obml_stretch_tl
\mathleading_set_default:nN { cases    } \l_obml_stretch_tl
\mathleading_set_default:nN { cases*   } \l_obml_stretch_tl
\mathleading_set_default:nN { aligned  } \l_obml_stretch_tl
\mathleading_set_default:nN { alignedat } \l_obml_stretch_tl
\mathleading_set_default:nN { gathered } \l_obml_stretch_tl

\splitleading_set_default:N \l_obml_stretch_tl 

\clist_if_in:NnF \g_opt_mlexception_clist { gather }
{
	\patchcmd \start@gather
	{ \collect@body }
	{ \linespread { \l_obml_stretch_tl } \selectfont \collect@body }
	{ }
	{ }
}

\clist_if_in:NnF \g_opt_mlexception_clist { align }
{
	\patchcmd \start@align
	{ \collect@body }
	{ \linespread { \l_obml_stretch_tl } \selectfont \collect@body }
	{ }
	{ }
}

\clist_if_in:NnF \g_opt_mlexception_clist { multline }
{
	\patchcmd \start@multline
	{ \collect@body }
	{ \linespread { \l_obml_stretch_tl } \selectfont \collect@body }
	{ }
	{ }
}



\bool_if:NF \g_noallowdispbreak_bool
{
	\AtBeginDocument { \allowdisplaybreaks }
}

%%% badm
\dim_new:N \l_beforedm_dim
\dim_new:N \l_afterdm_dim
\dim_new:N \l_defaultonebasedistance_dim

%%% for compatibility
%\cs_if_exist:NF \onelineskip { \let\onelineskip\baselineskip }
%\dim_set:Nn \l_defaultonebasedistance_dim { \baselineskip - \onelineskip }
%
%\NewDocumentCommand \setmlbeforeafterdm { mm }
%{
%	\dim_set:Nn \l_beforedm_dim { #1 }
%	\dim_set:Nn \l_afterdm_dim { #2 }
%}
%
%\bool_if:NT \opt_badm_bool
%{
%	\clist_set:Nn \l_tmpa_clist { align, equation, gather, multline, align*, equation*, gather*, alignat, alignat*, multline* }
%	\clist_map_inline:Nn \l_tmpa_clist 
%	{
%		\AddToHook { env/##1/before } { \vspace { \dimexpr-\l_defaultonebasedistance_dim - \l_beforedm_dim \relax } }
%		\AddToHook { env/##1/after } { \vspace { \dimexpr-\l_defaultonebasedistance_dim - \l_afterdm_dim \relax } }
%	}
%}


%% end of file