From: Father Chrysostomos <sprout@cpan.org>
Date: Wed, 1 Jun 2011 01:13:43 +0000 (-0700)
Subject: Allow rvalue syntax in expr returned from lvalue sub
X-Git-Tag: accepted/trunk/20130322.191538~3989
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=145b2bbb325a2181db2f44a0d0576e39e61b2e8b;p=platform%2Fupstream%2Fperl.git

Allow rvalue syntax in expr returned from lvalue sub

This changes the syntax of the last statement and the arguments to
‘return’ in an lvalue subroutine to be the same as that of a non-
lvalue routine. This almost finishes the work begun by commit fa1e92c.
(return still needs to enforce the same rules as leavesublv.)
---

diff --git a/op.c b/op.c
index e1bf353..c493a5f 100644
--- a/op.c
+++ b/op.c
@@ -1569,7 +1569,8 @@ Perl_op_lvalue(pTHX_ OP *o, I32 type)
     default:
       nomod:
 	/* grep, foreach, subcalls, refgen */
-	if (type == OP_GREPSTART || type == OP_ENTERSUB || type == OP_REFGEN)
+	if (type == OP_GREPSTART || type == OP_ENTERSUB
+	 || type == OP_REFGEN    || type == OP_LEAVESUBLV)
 	    break;
 	yyerror(Perl_form(aTHX_ "Can't modify %s in %s",
 		     (o->op_type == OP_NULL && (o->op_flags & OPf_SPECIAL)
diff --git a/t/op/sub_lval.t b/t/op/sub_lval.t
index 818dc60..787d904 100644
--- a/t/op/sub_lval.t
+++ b/t/op/sub_lval.t
@@ -3,7 +3,7 @@ BEGIN {
     @INC = '../lib';
     require './test.pl';
 }
-plan tests=>100;
+plan tests=>107;
 
 sub a : lvalue { my $a = 34; ${\(bless \$a)} }  # Return a temporary
 sub b : lvalue { ${\shift} }
@@ -260,16 +260,12 @@ eval <<'EOE' or $_ = $@;
   1;
 EOE
 
-like($_, qr/Can\'t modify index in lvalue subroutine return/);
+like($_, qr/Can\'t return a temporary from lvalue subroutine/);
 
 $_ = undef;
-eval <<'EOE' or $_ = $@;
-  sub lv2t : lvalue { shift }
-  (lv2t) = (2,3);
-  1;
-EOE
-
-like($_, qr/Can\'t modify shift in lvalue subroutine return/);
+sub lv2t : lvalue { shift }
+(lv2t($_)) = (2,3);
+is($_, 2);
 
 $xxx = 'xxx';
 sub xxx () { $xxx }  # Not lvalue
@@ -281,7 +277,7 @@ eval <<'EOE' or $_ = $@;
   1;
 EOE
 
-like($_, qr/Can\'t modify non-lvalue subroutine call in lvalue subroutine return/);
+is($_, undef, "returning a temp from an lvalue sub in scalar context");
 
 $_ = undef;
 eval <<'EOE' or $_ = $@;
@@ -291,14 +287,6 @@ EOE
 
 is($_, undef, "returning a temp from an lvalue sub in list context");
 
-$_ = undef;
-eval <<'EOE' or $_ = $@;
-  lv1tmp = 3;
-  1;
-EOE
-
-is($_, undef, "returning a temp from an lvalue sub in scalar context");
-
 sub yyy () { 'yyy' } # Const, not lvalue
 
 $_ = undef;
@@ -308,7 +296,7 @@ eval <<'EOE' or $_ = $@;
   1;
 EOE
 
-like($_, qr/Can\'t modify constant item in lvalue subroutine return/);
+like($_, qr/Can\'t return a readonly value from lvalue subroutine at/);
 
 $_ = undef;
 eval <<'EOE' or $_ = $@;
@@ -667,3 +655,28 @@ is $pnare, 1, 'and returning CATTLE actually works';
 $pnare = __PACKAGE__;
 ok eval { (fleen) = 1 }, "lvalues can return COWs in list context";
 is $pnare, 1, 'and returning COWs in list context actually works';
+
+
+# Returning an arbitrary expression, not necessarily lvalue
++sub :lvalue { return $ambaga || $ambaga }->() = 73;
+is $ambaga, 73, 'explicit return of arbitrary expression (scalar context)';
+(sub :lvalue { return $ambaga || $ambaga }->()) = 74;
+is $ambaga, 74, 'explicit return of arbitrary expression (list context)';
++sub :lvalue { $ambaga || $ambaga }->() = 73;
+is $ambaga, 73, 'implicit return of arbitrary expression (scalar context)';
+(sub :lvalue { $ambaga || $ambaga }->()) = 74;
+is $ambaga, 74, 'implicit return of arbitrary expression (list context)';
+{ local $::TODO = 'return needs to enforce the same rules as leavesublv';
+eval { +sub :lvalue { return 3 }->() = 4 };
+like $@, qr/Can\'t return a readonly value from lvalue subroutine at/,
+      'assignment to numeric constant explicitly returned from lv sub';
+eval { (sub :lvalue { return 3 }->()) = 4 };
+like $@, qr/Can\'t return a readonly value from lvalue subroutine at/,
+      'assignment to num constant explicitly returned (list cx)';
+}
+eval { +sub :lvalue { 3 }->() = 4 };
+like $@, qr/Can\'t return a readonly value from lvalue subroutine at/,
+      'assignment to numeric constant implicitly returned from lv sub';
+eval { (sub :lvalue { 3 }->()) = 4 };
+like $@, qr/Can\'t return a readonly value from lvalue subroutine at/,
+      'assignment to num constant implicitly returned (list cx)';