Remove unnecessary cons in lexical eval

* src/eval.c (list_of_t): New.
(Feval): Use list_of_t instead of consing every time.
(syms_of_eval): Set list_of_t to (t) and staticpro it.

diff --git a/src/eval.c b/src/eval.c
index d42f7ffe894559995c020e266cb36543dadb19e1..e377e30c6fb2e2604a74e9f592a0faa06ea73ab7 100644 (file)
--- a/src/eval.c
+++ b/src/eval.c
@@ -2348,6 +2348,8 @@ it defines a macro.  */)
 }
 
 \f
+static Lisp_Object list_of_t;  /* Never-modified constant containing (t).  */
+
 DEFUN ("eval", Feval, Seval, 1, 2, 0,
        doc: /* Evaluate FORM and return its value.
 If LEXICAL is t, evaluate using lexical scoping.
@@ -2357,7 +2359,7 @@ alist mapping symbols to their value.  */)
 {
   specpdl_ref count = SPECPDL_INDEX ();
   specbind (Qinternal_interpreter_environment,
-           CONSP (lexical) || NILP (lexical) ? lexical : list1 (Qt));
+           CONSP (lexical) || NILP (lexical) ? lexical : list_of_t);
   return unbind_to (count, eval_sub (form));
 }
 
@@ -4392,6 +4394,9 @@ alist of active lexical bindings.  */);
   Qcatch_all_memory_full
     = Fmake_symbol (build_pure_c_string ("catch-all-memory-full"));
 
+  staticpro (&list_of_t);
+  list_of_t = list1 (Qt);
+
   defsubr (&Sor);
   defsubr (&Sand);
   defsubr (&Sif);