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-rw-r--r--Master/texmf-dist/source/latex/l3kernel/l3tl.dtx32
1 files changed, 31 insertions, 1 deletions
diff --git a/Master/texmf-dist/source/latex/l3kernel/l3tl.dtx b/Master/texmf-dist/source/latex/l3kernel/l3tl.dtx
index 30ef7b74f8d..e6613f26e22 100644
--- a/Master/texmf-dist/source/latex/l3kernel/l3tl.dtx
+++ b/Master/texmf-dist/source/latex/l3kernel/l3tl.dtx
@@ -41,7 +41,7 @@
% }^^A
% }
%
-% \date{Released 2018-11-19}
+% \date{Released 2018-12-06}
%
% \maketitle
%
@@ -1009,6 +1009,23 @@
% \end{texnote}
% \end{function}
%
+% \begin{function}[EXP, added = 2016-12-06]
+% {\tl_rand_item:N, \tl_rand_item:c, \tl_rand_item:n}
+% \begin{syntax}
+% \cs{tl_rand_item:N} \meta{tl~var}
+% \cs{tl_rand_item:n} \Arg{token list}
+% \end{syntax}
+% Selects a pseudo-random item of the \meta{token list}. If the
+% \meta{token list} is blank, the result is empty. This is not yet
+% available in \XeTeX{}.
+% \begin{texnote}
+% The result is returned within the \tn{unexpanded}
+% primitive (\cs{exp_not:n}), which means that the \meta{item}
+% does not expand further when appearing in an \texttt{x}-type
+% argument expansion.
+% \end{texnote}
+% \end{function}
+%
% \section{Viewing token lists}
%
% \begin{function}[updated = 2015-08-01]{\tl_show:N, \tl_show:c}
@@ -2964,6 +2981,19 @@
% \end{macro}
% \end{macro}
%
+% \begin{macro}{\tl_rand_item:n, \tl_rand_item:N, \tl_rand_item:c}
+% Importantly \cs{tl_item:nn} only evaluates its argument once.
+% \begin{macrocode}
+\cs_new:Npn \tl_rand_item:n #1
+ {
+ \tl_if_blank:nF {#1}
+ { \tl_item:nn {#1} { \int_rand:nn { 1 } { \tl_count:n {#1} } } }
+ }
+\cs_new:Npn \tl_rand_item:N { \exp_args:No \tl_rand_item:n }
+\cs_generate_variant:Nn \tl_rand_item:N { c }
+% \end{macrocode}
+% \end{macro}
+%
% \subsection{Viewing token lists}
%
% \begin{macro}{\tl_show:N, \tl_show:c, \tl_log:N, \tl_log:c, \@@_show:NN}