[latex3-commits] [git/LaTeX3-latex3-latex2e] lthooks2: Clear the next_code token list once and before the code (8b97aee2)

[PhelypeOleinik]

Repository : https://github.com/latex3/latex2e
On branch  : lthooks2
Link       : https://github.com/latex3/latex2e/commit/8b97aee24e20c3aa577401c9b7e7428f9ee9147a

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

commit 8b97aee24e20c3aa577401c9b7e7428f9ee9147a
Author: PhelypeOleinik <tex.phelype at gmail.com>
Date:   Sat Aug 22 17:46:13 2020 -0300

    Clear the next_code token list once and before the code


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

8b97aee24e20c3aa577401c9b7e7428f9ee9147a
 base/lthooks.dtx                       | 25 +++++++++++++++++++-----
 base/testfiles-lthooks/lthooks-009.lvt | 17 +++++++++++++++++
 base/testfiles-lthooks/lthooks-009.tlg | 35 ++++++++++++++++++++++++++++++++++
 base/testfiles-lthooks/lthooks-010.tlg |  6 +++++-
 4 files changed, 77 insertions(+), 6 deletions(-)

diff --git a/base/lthooks.dtx b/base/lthooks.dtx
index eca2c763..54aede99 100644
--- a/base/lthooks.dtx
+++ b/base/lthooks.dtx
@@ -3120,7 +3120,7 @@
         \iow_term:x{~Extra~ code~ next~ invocation:}
         \iow_term:x{\@spaces
           \tl_if_empty:cTF { g_@@_#1_next_code_tl }
-            {---} {->~ \exp_args:NNc \exp_args:No \@@_log_next_code:n {g_@@_#1_next_code_tl} } }
+            {---} {->~ \exp_args:Nv \@@_log_next_code:n {g_@@_#1_next_code_tl} } }
 %    \end{macrocode}
 %
 %   Loop through the rules in a hook and for every rule found, print it.
@@ -3168,7 +3168,7 @@
 %    
 %    \begin{macrocode}
 \cs_new:Npn \@@_log_next_code:n #1 {
-  \exp_args:No \tl_to_str:n{\use_none:nn #1}    
+  \exp_args:No \tl_to_str:n {\use_none:nn #1}
 }
 %    \end{macrocode}
 %  \end{macro}
@@ -3259,10 +3259,25 @@
       { \@@_gput_next_do:nn {#1} {#2} }
       { \@@_try_declaring_generic_next_hook:nn {#1} {#2} }
   }
-\cs_new_protected:Npn \@@_gput_next_do:nn #1 #2
+\cs_new_protected:Npn \@@_gput_next_do:nn #1
   {
-    \tl_gput_right:cn { g_@@_#1_next_code_tl }
-      { #2 \tl_gclear:c { g_@@_#1_next_code_tl } }
+    \exp_args:Nc \@@_gput_next_do:Nnn
+      { g_@@_#1_next_code_tl } {#1}
+  }
+%    \end{macrocode}
+%   First check if the ``next code'' token list is empty:  if so we need
+%   to add a \cs{tl_gclear:c} to clear it, so the code lasts for one
+%   usage only.  The token list is cleared early so that nested usages
+%   don't get lost.  \cs{tl_gclear:c} is used instead of
+%   \cs{tl_gclear:N} in case the hook is used in an expansion-only
+%   context, so the token list doesn't expand before \cs{tl_gclear:N}:
+%   that would make an infinite loop.
+%    \begin{macrocode}
+\cs_new_protected:Npn \@@_gput_next_do:Nnn #1 #2
+  {
+    \tl_if_empty:NT #1
+      { \tl_gset:Nn #1 { \tl_gclear:c { g_@@_#2_next_code_tl } } }
+    \tl_gput_right:Nn #1
   }
 %    \end{macrocode}
 %  \end{macro}
diff --git a/base/testfiles-lthooks/lthooks-009.lvt b/base/testfiles-lthooks/lthooks-009.lvt
index a6bd1f1a..d232eec6 100644
--- a/base/testfiles-lthooks/lthooks-009.lvt
+++ b/base/testfiles-lthooks/lthooks-009.lvt
@@ -38,4 +38,21 @@
 \typeout{Nothing?}
 \textsf{E}  % nothing
 
+\def\hello{Hello, }
+
+\NewHook{hook}
+\AddToHookNext{hook}{\hello}
+\AddToHookNext{hook}{\AddToHookNext{hook}{nested}}
+\AddToHookNext{hook}{world!}
+\ShowHook{hook}
+
+\typeout{Use 'hook': \UseHook{hook}}
+\ShowHook{hook}
+
+\typeout{and again: \UseHook{hook}}
+\ShowHook{hook}
+
+\typeout{once more: \UseHook{hook}}
+\ShowHook{hook}
+
 \end{document}
diff --git a/base/testfiles-lthooks/lthooks-009.tlg b/base/testfiles-lthooks/lthooks-009.tlg
index 8da7a10e..060beb9a 100644
--- a/base/testfiles-lthooks/lthooks-009.tlg
+++ b/base/testfiles-lthooks/lthooks-009.tlg
@@ -68,6 +68,41 @@ Std sffamily code
 Update code for hook 'sffamily' on input line ...:
 only this code
 Nothing?
+The hook 'hook':
+ Code chunks:
+    ---
+ Extra code next invocation:
+    -> \hello \AddToHookNext {hook}{nested}world!
+ Rules:
+    ---
+ Execution order:
+Use 'hook': 
+The hook 'hook':
+ Code chunks:
+    ---
+ Extra code next invocation:
+    -> \hello \AddToHookNext {hook}{nested}world!
+ Rules:
+    ---
+ Execution order:
+and again: 
+The hook 'hook':
+ Code chunks:
+    ---
+ Extra code next invocation:
+    -> \hello \AddToHookNext {hook}{nested}world!
+ Rules:
+    ---
+ Execution order:
+once more: 
+The hook 'hook':
+ Code chunks:
+    ---
+ Extra code next invocation:
+    -> \hello \AddToHookNext {hook}{nested}world!
+ Rules:
+    ---
+ Execution order:
 Absolute page = 1 (target: 1)
 [1
 ] (lthooks-009.aux)
diff --git a/base/testfiles-lthooks/lthooks-010.tlg b/base/testfiles-lthooks/lthooks-010.tlg
index 5ab2af2a..050d969b 100644
--- a/base/testfiles-lthooks/lthooks-010.tlg
+++ b/base/testfiles-lthooks/lthooks-010.tlg
@@ -13,7 +13,7 @@ The hook 'sffamily':
     foo -> foo code
     bar -> bar code
  Extra code next invocation:
-    -> first occasion only\tl_gclear:c {g__hook_sffamily_next_code_tl}
+    -> first occasion only $\frac 12$
  Rules:
     foo|bar with relation >
  Execution order (after applying rules):
@@ -33,6 +33,10 @@ LaTeX Font Info:    Checking defaults for OMX/cmex/m/n on input line ....
 LaTeX Font Info:    ... okay on input line ....
 LaTeX Font Info:    Checking defaults for U/cmr/m/n on input line ....
 LaTeX Font Info:    ... okay on input line ....
+LaTeX Font Info:    External font `cmex10' loaded for size
+(Font)              <7> on input line ....
+LaTeX Font Info:    External font `cmex10' loaded for size
+(Font)              <5> on input line ....
 The hook 'sffamily':
  Code chunks:
     legacy -> Std sffamily code