Fix infinite loop in the example on Loops over list of items provided under Section 2.6.2 of TeX-programming-notes.tex

doc/latex/pgfplots/ChangeLog

@@ -1,3 +1,8 @@
+2024-07-10 Hanson Char <[email protected]> and plante <[email protected]>
+
+	Fix infinite loop in the example on Loops over list of items provided
+	under Section 2.6.2 of TeX-programming-notes.tex
+
 2021-12-27 Christian Feuersaenger <[email protected]>
 
 	fix linux file read permissions of some new lua files in TDS zip

doc/latex/pgfplots/TeX-programming-notes.tex

@@ -920,7 +920,7 @@ \subsubsection{Loops over list of items}
 Looping over a list of items is very similar, only we will need |\ifx| in place of |\ifnum| and we need some end marker instead of the threshold value. However, how do we specify the list itself? Let's make some comma-separated list, e.\,g. |{a,b,c,d}| and call the end marker |\listingloopENDMARKER|.
 
 \begin{codeexample}[]
-\def\listingloopENDMARKER{\par \listingloopENDMARKER}
+\def\listingloopENDMARKER{\listingloopENDMARKER}
 \long\def\listingloop#1in#2#3{%
 	\looppicker{#1}{#3}#2,\listingloopENDMARKER,%
 }%
@@ -933,18 +933,18 @@ \subsubsection{Loops over list of items}
 		#2%
 		\def\next{\looppicker{#1}{#2}}%
 	\fi
-	\next
+	\next%
 }%
-\listingloop\x in{a,b,c,,d,e}{%
-	The current item is `\x'
+\listingloop\x in{aa, b,c ,,d,e}{%
+	The current item is `\x'\par
 }
 \end{codeexample}
 
 Again, we make clear the subtleties contained therein:
 \begin{itemize}
  \item We have defined |\listingloopENDMARKER| to replace itself. This is possible because |\ifx| will only compare first-level expansion, see Section~\ref{sec:branching}.
  \item We seem to miss a white space in \ldots|#1in#2|\ldots. However, tokens are always ending with an additional white space as |\xin| is not equal to |\x in|. Hence, none is needed here and more than one white space would probably get gobbled.
- \item The definition |\looppicker#1#2#3,|\ldots has three arguments but the recursive call |\looppicker{#1}{#2}| only gives two arguments!? This is the actual magic making this type of list possible! \TeX{} is actually scanning beyond the scope of the given token to obtain the third argument. In effect, we are biting off piece by piece, list item by list item off the given list. All because we have stated an additional |,| -- comma being the item separator -- in the definition of the |\looppicker| macro. The expansion of the loop macro will always pick up one more item from the list concatenated to its end until it has reached the |\ENDMARKER|. This is added to the list's very end on the loop's start, and there it stops.
+ \item The definition |\looppicker#1#2#3,|\ldots has three arguments but the recursive call |\looppicker{#1}{#2}| only gives two arguments!? This is the actual magic making this type of list possible! \TeX{} is actually scanning beyond the scope of the given token to obtain the third argument. In effect, we are biting off piece by piece, list item by list item off the given list. All because we have stated an additional |,| -- comma being the item separator -- in the definition of the |\looppicker| macro. The expansion of the loop macro will always pick up one more item from the list concatenated to its end until it has reached the |\listingloopENDMARKER|. This is added to the list's very end on the loop's start, and there it stops.
 \end{itemize}
 
 \subsection{More On \TeX}