add code macro usable inside other environments

src/wip/code/code.pysty

@@ -7,15 +7,18 @@ __NEW_IF__(pipe,false)
 \catcode`_=13
 \let_\_
 \catcode`_=8
-\newcommand\code{
-  \begingroup
-  \catcode`_=\active
-  \code@impl
-}
-\newcommand\code@impl[1]{
-  \texttt{#1}
-  \endgroup
-}
+
+\ExplSyntaxOn
+\NewDocumentCommand{\code}{m}
+  {
+    \tl_set_rescan:Nnn \l_tmpa_tl
+    {
+      \char_set_catcode_active:N _
+    }
+    { #1 }
+    \texttt{ \tl_use:N \l_tmpa_tl }
+  }
+\ExplSyntaxOff
 
 \newif\ifactive\activefalse
 __IF__(pipe)