From 33aff2d593d60382ba6f85c9753502fc4c206f4a Mon Sep 17 00:00:00 2001
From: Andrew Stacey <loopspace@mathforge.org>
Date: Fri, 12 Apr 2024 21:06:17 +0100
Subject: [PATCH] Patches TikZ's foreach to remember more information between
 iterations

This commit adds more information to what TikZ remembers between foreach
iterations, and does so in a way that makes it easier to add other
macros and dimensions to the list of things it remembers, both at the
code level and via keys.

Fixes #356, #1047, #1303, #1313

Signed-off-by: Andrew Stacey <loopspace@mathforge.org>
---
 doc/generic/pgf/CHANGELOG.md                  |  1 +
 .../pgf/frontendlayer/tikz/tikz.code.tex      | 78 +++++++++++++++----
 2 files changed, 63 insertions(+), 16 deletions(-)

diff --git a/doc/generic/pgf/CHANGELOG.md b/doc/generic/pgf/CHANGELOG.md
index d27a1ab42..67b5ace4b 100644
--- a/doc/generic/pgf/CHANGELOG.md
+++ b/doc/generic/pgf/CHANGELOG.md
@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Fixed
 
+- Foreach in path remembers nodes between iterations #356, #1047, #1303, #1313
 - Typo in animations `end on` key #1273
 - Output bounding box adjustment in pgfsys-dvisvgm.def #1275
 - Fix shadings under LuaMetaTeX
diff --git a/tex/generic/pgf/frontendlayer/tikz/tikz.code.tex b/tex/generic/pgf/frontendlayer/tikz/tikz.code.tex
index d9b1743b9..31d260c02 100644
--- a/tex/generic/pgf/frontendlayer/tikz/tikz.code.tex
+++ b/tex/generic/pgf/frontendlayer/tikz/tikz.code.tex
@@ -2580,28 +2580,77 @@
 
 \def\tikz@fchar oreach{\tikz@foreach}%
 
+%
+% These are to allow \foreach to remember macros and dimensions between iterations
+%
+  
+\def\tikzforeach@smugglers@cove{}
+\let\tikztostart=\relax
+
+\def\tikzforeach@smuggle@macro#1{%
+  \pgfutil@ifx#1\relax{}{%
+    \expandafter
+    \pgfutil@g@addto@macro
+    \expandafter
+    \tikzforeach@smugglers@cove
+    \expandafter
+    {%
+      \expandafter\def\expandafter#1\expandafter{#1}%
+    }%
+  }%
+}
+
+\def\tikzforeach@smuggle@dimen#1{%
+  \pgfutil@ifx#1\relax{}{%
+    \expandafter
+    \pgfutil@g@addto@macro
+    \expandafter
+    \tikzforeach@smugglers@cove
+    \expandafter
+    {%
+      \expandafter#1\expandafter=\the#1\relax%
+    }%
+  }%
+}
+
+\def\tikzforeach@smugglers@loot{%
+  %
+  \tikzforeach@smuggle@macro\tikz@moveto@waiting%
+  \tikzforeach@smuggle@macro\tikztostart%
+  \tikzforeach@smuggle@macro\tikz@tangent%
+  %
+  \tikzforeach@smuggle@dimen\tikz@lastx%
+  \tikzforeach@smuggle@dimen\tikz@lasty%
+  \tikzforeach@smuggle@dimen\tikz@lastxsaved%
+  \tikzforeach@smuggle@dimen\tikz@lastysaved%
+  %
+}
+
+\tikzset{
+  remember macro/.code={
+    \tikzforeach@smuggle@macro#1
+  },
+  remember dimension/.code={
+    \tikzforeach@smuggle@dimen#1
+  }
+}
+
+
 \def\tikz@foreach{%
   \def\pgffor@beginhook{%
-    \tikz@lastx=\tikz@foreach@save@lastx%
-    \tikz@lasty=\tikz@foreach@save@lasty%
-    \tikz@lastxsaved=\tikz@foreach@save@lastxsaved%
-    \tikz@lastysaved=\tikz@foreach@save@lastysaved%
+    \tikzforeach@smugglers@cove%
+    \gdef\tikzforeach@smugglers@cove{}%
     \setbox\tikz@figbox=\box\tikz@tempbox%
     \setbox\tikz@figbox@bg=\box\tikz@tempbox@bg%
     \expandafter\tikz@scan@next@command\pgfutil@firstofone}%
   \def\pgffor@endhook{\pgfextra{%
-      \xdef\tikz@foreach@save@lastx{\the\tikz@lastx}%
-      \xdef\tikz@foreach@save@lasty{\the\tikz@lasty}%
-      \xdef\tikz@foreach@save@lastxsaved{\the\tikz@lastxsaved}%
-      \xdef\tikz@foreach@save@lastysaved{\the\tikz@lastysaved}%
+      \tikzforeach@smugglers@loot%
       \global\setbox\tikz@tempbox=\box\tikz@figbox%
       \global\setbox\tikz@tempbox@bg=\box\tikz@figbox@bg%
       \pgfutil@gobble}}%
   \def\pgffor@afterhook{%
-    \tikz@lastx=\tikz@foreach@save@lastx%
-    \tikz@lasty=\tikz@foreach@save@lasty%
-    \tikz@lastxsaved=\tikz@foreach@save@lastxsaved%
-    \tikz@lastysaved=\tikz@foreach@save@lastysaved%
+    \tikzforeach@smugglers@cove%
+    \gdef\tikzforeach@smugglers@cove{}%
     \let\pgffor@beginhook\relax%
     \let\pgffor@endhook\relax%
     \let\pgffor@afterhook\relax%
@@ -2610,10 +2659,7 @@
     \tikz@scan@next@command}%
   \global\setbox\tikz@tempbox=\box\tikz@figbox%
   \global\setbox\tikz@tempbox@bg=\box\tikz@figbox@bg%
-  \xdef\tikz@foreach@save@lastx{\the\tikz@lastx}%
-  \xdef\tikz@foreach@save@lasty{\the\tikz@lasty}%
-  \xdef\tikz@foreach@save@lastxsaved{\the\tikz@lastxsaved}%
-  \xdef\tikz@foreach@save@lastysaved{\the\tikz@lastysaved}%
+  \tikzforeach@smugglers@loot%
   \foreach}%