[latex3-commits] [git/LaTeX3-latex3-latex3] main: Document scratch variables (closes #973) (b7f4a94b6)

[Joseph Wright]

Repository : https://github.com/latex3/latex3
On branch  : main
Link       : https://github.com/latex3/latex3/commit/b7f4a94b695fcee418906f4051f7d7ecab5eb0cd

>---------------------------------------------------------------

commit b7f4a94b695fcee418906f4051f7d7ecab5eb0cd
Author: Joseph Wright <joseph.wright at morningstar2.co.uk>
Date:   Mon Aug 2 14:03:15 2021 +0100

    Document scratch variables (closes #973)


>---------------------------------------------------------------

b7f4a94b695fcee418906f4051f7d7ecab5eb0cd
 l3kernel/doc/source3body.tex | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/l3kernel/doc/source3body.tex b/l3kernel/doc/source3body.tex
index 946f7a4ab..ff564f170 100644
--- a/l3kernel/doc/source3body.tex
+++ b/l3kernel/doc/source3body.tex
@@ -328,6 +328,14 @@ following variable types:
   \item[\texttt{regex}] Regular expression.
 \end{description}
 
+\subsection{Scratch variables}
+
+Modules focussed on variable usage typically provide four scratch variables,
+two local and two global, with names of the form
+\cs{\meta{scope}_tmp(a|b)_\meta{type}}. These are never used by the core code.
+The nature of \TeX{} grouping means that as with any other scratch variable,
+these should only be set and used with no intervening third-party code.
+
 \subsection{Terminological inexactitude}
 
 A word of warning. In this document, and others referring to the \pkg{expl3}