From 15fc6a83b0ecaa076e6e0a6daf44ed6959b7cbcc Mon Sep 17 00:00:00 2001
From: Will Robertson <wspr81@gmail.com>
Date: Sun, 12 May 2024 19:44:52 +0930
Subject: [PATCH] code doc update (fontload)

again #496
---
 fontspec-code-fontload.dtx | 67 +++++++++++++++++++++++++++++++++++---
 1 file changed, 63 insertions(+), 4 deletions(-)

diff --git a/fontspec-code-fontload.dtx b/fontspec-code-fontload.dtx
index 4b36515..44bb9b9 100644
--- a/fontspec-code-fontload.dtx
+++ b/fontspec-code-fontload.dtx
@@ -2,6 +2,65 @@
 
 % \section{expl3 interface for primitive font loading}
 %
+% \begin{function}{\@@_primitive_font_set:Nnn,\@@_primitive_font_gset:Nnn}
+% \begin{syntax}
+% |\@@_primitive_font_set:Nnn| \meta{font cs} \Arg{file/name} \Arg{size (dim.\ expr)}
+% \end{syntax}
+% Wrapper around \TeX\ \cs{font} primitive.
+% \end{function}
+%
+% \begin{function}{\@@_font_suppress_not_found_error:}
+% Wrapper around \XeTeX\/Lua\TeX\ primitive, used to be able to programmatically query font existence.
+% \end{function}
+%
+% \begin{function}[pTF]{\@@_primitive_font_if_null:N}
+% \begin{syntax}
+% |\@@_primitive_font_if_null:NTF| \meta{font cs} \Arg{true code} \Arg{false code}
+% \end{syntax}
+% Query whether the \meta{font cs} is the \cs{nullfont}.
+% \end{function}
+%
+% \begin{function}[TF]{\@@_primitive_font_set:Nnn,\@@_primitive_font_gset:Nnn}
+% \begin{syntax}
+% |\@@_primitive_font_set:NnnTF| \meta{font cs} \Arg{file/name} \Arg{size (dim.\ expr)} \Arg{true code} \Arg{false code}
+% \end{syntax}
+% Attempts to set the \meta{font cs} and provide branching for success or failure according to whether the font exists.
+% \end{function}
+%
+% \begin{function}[TF]{\@@_primitive_font_if_exist:n}
+% \begin{syntax}
+% |\@@_primitive_font_if_exist:nTF| \Arg{file/name} \Arg{true code} \Arg{false code}
+% \end{syntax}
+% Attempts to load the font at the current font size minus 1\,sp with a dummy meta{font cs}
+% (\verb|\l_@@_primitive_font|), and branches according to whether the font exists.
+% This is intended to be used speculatively before potentially performing additional processing
+% steps (e.g., an analysis of available font features) before setting up the `true' font.
+% \end{function}
+%
+% \begin{function}[pTF]{\@@_primitive_font_glyph_if_exist:Nn}
+% \begin{syntax}
+% |\@@_primitive_font_glyph_if_exist:nTF| \meta{font cs} \Arg{char. number (int.\ expr)} \Arg{true code} \Arg{false code}
+% \end{syntax}
+% Wrapper around primitive \cs{iffontchar}.
+% \end{function}
+%
+% \begin{function}{\@@_primitive_font_set_hyphenchar:Nn}
+% \begin{syntax}
+% |\@@_primitive_font_set_hyphenchar:Nn| \meta{font cs} \Arg{char. number (int.\ expr)}
+% \end{syntax}
+% Setter function around primitive \cs{hyphenchar}.
+% \end{function}
+%
+% \begin{function}{\@@_primitive_font_get_name:N,\@@_primitive_font_current_name:}
+% \begin{syntax}
+% |\@@_primitive_font_get_name:N| \meta{font cs}
+% \end{syntax}
+% Wrapper function around \TeX\ primitive \cs{fontname}. The no-argument version is
+% equivalent to \verb|\fontname\font|.
+% \end{function}
+%
+% \section{Implementation}
+% 
 % \iffalse
 %    \begin{macrocode}
 %<*fontspec>
@@ -45,7 +104,7 @@
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}[pTF]{\@@_primitive_font_set:NnnTF,\@@_primitive_font_gset:NnnTF}
+% \begin{macro}[TF]{\@@_primitive_font_set:Nnn,\@@_primitive_font_gset:Nnn}
 %    \begin{macrocode}
 \prg_new_conditional:Nnn \@@_primitive_font_set:Nnn {TF,T,F}
   {
@@ -78,11 +137,11 @@
 %    \end{macrocode}
 % \end{macro}
 %
-% \begin{macro}{\@@_primitive_font_glyph_if_exist:NnTF}
+% \begin{macro}[pTF]{\@@_primitive_font_glyph_if_exist:Nn}
 %    \begin{macrocode}
 \prg_new_conditional:Nnn \@@_primitive_font_glyph_if_exist:Nn {p,TF,T,F}
   {
-    \tex_iffontchar:D #1 #2 \scan_stop:
+    \tex_iffontchar:D #1 \int_eval:n {#2} \scan_stop:
       \prg_return_true:
     \else:
       \prg_return_false:
@@ -95,7 +154,7 @@
 %    \begin{macrocode}
 \cs_new:Nn \@@_primitive_font_set_hyphenchar:Nn
   {
-     \tex_hyphenchar:D #1 = #2 \scan_stop:
+     \tex_hyphenchar:D #1 = \int_eval:n {#2} \scan_stop:
   }
 %    \end{macrocode}
 % \end{macro}