Pragma inside grep block

rovf has asked for the wisdom of the Perl Monks concerning the following question:

Why does Perl 5.8.8 complain "no" not allowed in expression in this program:

use strict; use warnings;
grep { no strict 'refs'; }qw(x);
[download]

but not in this:

use strict; use warnings;
grep { 0; no strict 'refs'; }qw(x);
[download]

--
Ronald Fischer <ynnor@mm.st>

Comment on Pragma inside grep block Select or Download Code

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Re: Pragma inside grep block by moritz (Cardinal) on Jul 08, 2009 at 12:04 UTC
Because perl mis-parses this for `grep HASHREF` (but I have no idea why), expects a statement, sees a 'no' and complains. Yes, this could be done better, but fiddling with the perl 5 lexer is non-trivial and not for the faint of hearted.	[reply] [d/l]
Re: Pragma inside grep block by RMGir (Prior) on Jul 08, 2009 at 12:08 UTC
Good question. 5.10.0 has the same problem: `$ perl -e'use strict; use warnings; grep { no strict "refs"; }qw(x); ' "no" not allowed in expression at -e line 2, at end of line BEGIN not safe after errors--compilation aborted at -e line 2. $ perl -e'use strict; use warnings; grep { 0; no strict "refs"; }qw(x); ' $` [download] Of course, `{ no strict "refs"; grep {0;} qw(x); }` [download] would work fine, so at least there's a workaround... Mike	[reply] [d/l] [select]
Re^2: Pragma inside grep block by Anonymous Monk on Jul 08, 2009 at 12:16 UTC
Workaround is to add ; `grep { ;no strict 'refs'; } qw(x);` [download] but that confuse Deparse :D `perl -MO=Deparse use strict; use warnings; grep { ;no strict 'refs'; } qw(x); ^D use warnings; use strict 'refs'; grep {();} 'x'; - syntax OK` [download] Also works `grep { do{ no strict 'refs'; } } qw(x)` [download]	[reply] [d/l] [select]