Evaluate int constants only once (fixes #861)

latex3 · Feb 27, 2021 · eac3d1d · eac3d1d
1 parent b995ab2
commit eac3d1d
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Showing 2 changed files with 13 additions and 6 deletions.
diff --git a/l3kernel/CHANGELOG.md b/l3kernel/CHANGELOG.md
@@ -7,6 +7,9 @@ this project uses date-based 'snapshot' version identifiers.
 
 ## [Unreleased]
 
+### Fixed
+- Evalutate integer constants only once (issue#861)
+
 ### Deprecated
 - `l3docstrip` converted to a stub which simply loads DocStrip: use
    the latter directly 

diff --git a/l3kernel/l3int.dtx b/l3kernel/l3int.dtx
@@ -1282,6 +1282,7 @@
 % \end{macro}
 %
 % \begin{macro}{\int_const:Nn, \int_const:cn}
+% \begin{macro}{\@@_const:nN}
 % \begin{macro}{\@@_constdef:Nw}
 % \begin{variable}{\c_@@_max_constdef_int}
 % \UnitTested
@@ -1293,24 +1294,26 @@
 %   enabled) this runs some checks that constants would fail.
 %    \begin{macrocode}
 \cs_new_protected:Npn \int_const:Nn #1#2
+  { \exp_args:Ne \@@_const:nN { \int_eval:n {#2} } #1 }
+\cs_new_protected:Npn \@@_const:nN #1#2
   {
-    \int_compare:nNnTF {#2} < \c_zero_int
+    \int_compare:nNnTF {#1} < \c_zero_int
       {
-        \int_new:N #1
+        \int_new:N #2
         \tex_global:D
       }
       {
-        \int_compare:nNnTF {#2} > \c_@@_max_constdef_int
+        \int_compare:nNnTF {#1} > \c_@@_max_constdef_int
           {
-            \int_new:N #1
+            \int_new:N #2
             \tex_global:D
           }
           {
-            \__kernel_chk_if_free_cs:N #1
+            \__kernel_chk_if_free_cs:N #2
             \tex_global:D \@@_constdef:Nw
           }
       }
-    #1 = \@@_eval:w #2 \@@_eval_end:
+    #2 = \@@_eval:w #1 \@@_eval_end:
   }
 \cs_generate_variant:Nn \int_const:Nn { c }
 \if_int_odd:w 0
@@ -1329,6 +1332,7 @@
 % \end{variable}
 % \end{macro}
 % \end{macro}
+% \end{macro}
 %
 % \begin{macro}{\int_zero:N, \int_zero:c}
 % \UnitTested