Re: exists &sub (was: exists $foo[7] and delete $foo[7])

[Spider Boardman <spider-perl@Orb.Nashua.NH.US>]

On Wed, 19 Jan 2000 11:03:18 -0500, Ronald J Kimball wrote (in part):

rjk> One little typo...

Good catch.  Thanks.  The attached fixes that, along with an improper bogus
error once other errors have already been seen.

Specifically,

	sub foo {1;}
	undef foo;	# note missing & on foo
	exists &foo;

This example would correctly report the improper use of &foo as
an lvalue, but would then go on to complain that the argument to
exists is not a subroutine name.  The patch below makes it err in
the other direction, so that now this example:

	sub foo {1;}
	undef foo;	# note missing & on foo
	exists &foo();

will be silent about the second error.  This 'feels' better than
generating the bogus error on the correct construct as in the
first example.

	--s.

--- ./pod/perlfunc.pod.PREV	Wed Jan 19 11:40:52 2000
+++ ./pod/perlfunc.pod	Wed Jan 19 11:43:23 2000
@@ -1423,7 +1423,7 @@ A hash or array element can be true only
 it exists, but the reverse doesn't necessarily hold true.
 
 Given an expression that specifies the name of a subroutine,
-returns true of the specified subroutine has ever been declared, even
+returns true if the specified subroutine has ever been declared, even
 if it is undefined.  Mentioning a subroutine name for exists or defined
 does not count as declaring it.
 
--- ./op.c.PREV	Wed Jan 19 11:40:53 2000
+++ ./op.c	Wed Jan 19 11:42:31 2000
@@ -5035,7 +5035,7 @@ Perl_ck_exists(pTHX_ OP *o)
 	OP *kid = cUNOPo->op_first;
 	if (kid->op_type == OP_ENTERSUB) {
 	    (void) ref(kid, o->op_type);
-	    if (kid->op_type != OP_RV2CV)
+	    if (kid->op_type != OP_RV2CV && !PL_error_count)
 		Perl_croak(aTHX_ "%s argument is not a subroutine name",
 			   PL_op_desc[o->op_type]);
 	    o->op_private |= OPpEXISTS_SUB;

---

References to:

Larry Wall <larry@wall.org>
spider-perl@Orb.Nashua.NH.US
Ronald J Kimball <rjk@linguist.dartmouth.edu>

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