From: Gurusamy Sarathy <gsar@cpan.org>
Date: Mon, 8 Feb 1999 14:40:23 +0000 (+0000)
Subject: make qw() into a true list at compile time (slightly modified
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=8127e0e3c3aeffc5d0bcdebd664c0fd7cd5bd9fe;p=p5sagit%2Fp5-mst-13.2.git

make qw() into a true list at compile time (slightly modified
variant of patch suggested by Tom Hughes <tom@compton.demon.co.uk>)

p4raw-id: //depot/perl@2835
---

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index b2e197f..0de44db 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -107,6 +107,11 @@ behavior of:
 
 remains unchanged.  See L<perlop>.
 
+=item Improved C<qw//> operator
+
+The C<qw//> operator is now evaluated at compile time instead of being
+replaced with a run time call to C<split()>.
+
 =head1 Supported Platforms
 
 =over 4
diff --git a/pod/perlop.pod b/pod/perlop.pod
index 0b848ad..4b49808 100644
--- a/pod/perlop.pod
+++ b/pod/perlop.pod
@@ -1040,13 +1040,13 @@ See L<"I/O Operators"> for more discussion.
 
 =item qw/STRING/
 
-Returns a list of the words extracted out of STRING, using embedded
-whitespace as the word delimiters.  It is exactly equivalent to
+Evaluates to a list of the words extracted out of STRING, using embedded
+whitespace as the word delimiters.  It can be understood as being roughly
+equivalent to:
 
     split(' ', q/STRING/);
 
-This equivalency means that if used in scalar context, you'll get split's
-(unfortunate) scalar context behavior, complete with mysterious warnings.
+the difference being that it generates a real list at compile time.
 
 Some frequently seen examples:
 
diff --git a/pp_hot.c b/pp_hot.c
index 98763b8..f304e8b 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -655,7 +655,7 @@ PP(pp_aassign)
 		    if (SvSMAGICAL(sv))
 			mg_set(sv);
 		    if (!didstore)
-			SvREFCNT_dec(sv);
+			sv_2mortal(sv);
 		}
 		TAINT_NOT;
 	    }
@@ -682,7 +682,7 @@ PP(pp_aassign)
 			if (SvSMAGICAL(tmpstr))
 			    mg_set(tmpstr);
 			if (!didstore)
-			    SvREFCNT_dec(tmpstr);
+			    sv_2mortal(tmpstr);
 		    }
 		    TAINT_NOT;
 		}
@@ -704,7 +704,7 @@ PP(pp_aassign)
 			    if (SvSMAGICAL(tmpstr))
 				mg_set(tmpstr);
 			    if (!didstore)
-				SvREFCNT_dec(tmpstr);
+				sv_2mortal(tmpstr);
 			}
 			TAINT_NOT;
 		    }
diff --git a/toke.c b/toke.c
index 22344b4..4ab20c2 100644
--- a/toke.c
+++ b/toke.c
@@ -3838,36 +3838,46 @@ int yylex(PERL_YYLEX_PARAM_DECL)
 	    s = scan_str(s);
 	    if (!s)
 		missingterm((char*)0);
-	    if (ckWARN(WARN_SYNTAX) && SvLEN(PL_lex_stuff)) {
+	    force_next(')');
+	    if (SvCUR(PL_lex_stuff)) {
+		OP *words = Nullop;
+		int warned = 0;
 		d = SvPV_force(PL_lex_stuff, len);
-		for (; len; --len, ++d) {
-		    if (*d == ',') {
-			warner(WARN_SYNTAX,
-			    "Possible attempt to separate words with commas");
-			break;
-		    }
-		    if (*d == '#') {
-			warner(WARN_SYNTAX,
-			    "Possible attempt to put comments in qw() list");
-			break;
+		while (len) {
+		    for (; isSPACE(*d) && len; --len, ++d) ;
+		    if (len) {
+			char *b = d;
+			if (!warned && ckWARN(WARN_SYNTAX)) {
+			    for (; !isSPACE(*d) && len; --len, ++d) {
+				if (*d == ',') {
+				    warner(WARN_SYNTAX,
+					"Possible attempt to separate words with commas");
+				    ++warned;
+				}
+				else if (*d == '#') {
+				    warner(WARN_SYNTAX,
+					"Possible attempt to put comments in qw() list");
+				    ++warned;
+				}
+			    }
+			}
+			else {
+			    for (; !isSPACE(*d) && len; --len, ++d) ;
+			}
+			words = append_elem(OP_LIST, words,
+					    newSVOP(OP_CONST, 0, newSVpvn(b, d-b)));
 		    }
 		}
+		if (words) {
+		    PL_nextval[PL_nexttoke].opval = words;
+		    force_next(THING);
+		}
 	    }
-	    force_next(')');
-	    PL_nextval[PL_nexttoke].opval = (OP*)newSVOP(OP_CONST, 0, tokeq(PL_lex_stuff));
+	    if (PL_lex_stuff)
+		SvREFCNT_dec(PL_lex_stuff);
 	    PL_lex_stuff = Nullsv;
-	    force_next(THING);
-	    force_next(',');
-	    PL_nextval[PL_nexttoke].opval = (OP*)newSVOP(OP_CONST, 0, newSVpv(" ",1));
-	    force_next(THING);
-	    force_next('(');
-	    yylval.ival = OP_SPLIT;
-	    CLINE;
 	    PL_expect = XTERM;
-	    PL_bufptr = s;
-	    PL_last_lop = PL_oldbufptr;
-	    PL_last_lop_op = OP_SPLIT;
-	    return FUNC;
+	    TOKEN('(');
 
 	case KEY_qq:
 	    s = scan_str(s);