Fix inconsistency in regex-source.

If we compile the regex expression (compound "str*"), calling
regex-source on the compiled regex object yields "str*".
That, of course, is treated as regex character syntax if
fed back to regex-compile, and the * becomes an operator.

We want the source to be (compound "str*").

This happens because the AST optimizer reduces
(compound X) -> X.

* regex.c (regex_compile): If the optimized expression is just
a character string atom S, then for the purposes of
maintaining the source code, convert it to (compound S).

1 files changed, 8 insertions, 2 deletions

diff --git a/regex.c b/regex.c
index 1f645ead..00611d2a 100644
--- a/regex.c
+++ b/regex.c
@@ -2101,6 +2101,8 @@ static val regex_requires_dv(val exp)
 
 val regex_compile(val regex_sexp, val error_stream)
 {
+  val regex_source;
+
   if (stringp(regex_sexp)) {
     regex_sexp = regex_parse(regex_sexp, default_bool_arg(error_stream));
     return if2(regex_sexp, regex_compile(regex_sexp, error_stream));
@@ -2108,6 +2110,10 @@ val regex_compile(val regex_sexp, val error_stream)
 
   regex_sexp = reg_optimize(reg_expand_nongreedy(reg_nary_to_bin(regex_sexp)));
 
+  regex_source = if3(stringp(regex_sexp),
+                     cons(compound_s, cons(regex_sexp, nil)),
+                     regex_sexp);
+
   if (opt_derivative_regex || regex_requires_dv(regex_sexp)) {
     regex_t *regex = coerce(regex_t *, chk_malloc(sizeof *regex));
     val ret;
@@ -2117,7 +2123,7 @@ val regex_compile(val regex_sexp, val error_stream)
     regex->source = nil;
     ret = cobj(coerce(mem_t *, regex), regex_s, &regex_obj_ops);
     regex->r.dv = dv;
-    regex->source = regex_sexp;
+    regex->source = regex_source;
     return ret;
   } else {
     regex_t *regex = coerce(regex_t *, chk_malloc(sizeof *regex));
@@ -2127,7 +2133,7 @@ val regex_compile(val regex_sexp, val error_stream)
     ret = cobj(coerce(mem_t *, regex), regex_s, &regex_obj_ops);
     regex->r.nfa = nfa_compile_regex(regex_sexp);
     regex->nstates = nfa_count_states(regex->r.nfa.start);
-    regex->source = regex_sexp;
+    regex->source = regex_source;
     return ret;
   }
 }