Re: statement vs. block?

Something like this?

our ($For, $While, $Map, $Grep, $If) =
  qw( For   While   Map   Grep   If)
;

local $For = 'local' for 1;
local $While = 'local' while ! $a++;
map +(local $Map = 'local'), 1;
grep +(local $Grep = 'local'), 1;
local $If = 'local' if 1;

print "For:   $For\n";
print "While: $While\n";
print "Map:   $Map\n";
print "Grep:  $Grep\n";
print "If:    $If\n";

__END__
For:   For
While: While
Map:   Map
Grep:  Grep
If:    local
[download]

Here, all loop constructs introduces a scope for the expression just as they would if it was a block. if however doesn't.

While speaking about blocks for map and grep (and sort):

map { use strict; } LIST
[download]

fails with '"use" not allowed in expression ...'. A do block can be used to ~~"upgrade" the block though~~ avoid the ambiguity (see ysth's reply:

map do { use strict; }, LIST
[download]

works. (Interestingly, this uses map EXPR, LIST ...)

lodin

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Re^2: statement vs. block? by ysth (Canon) on Apr 13, 2008 at 04:59 UTC
`map { use strict; } LIST` [download] fails with '"use" not allowed in expression ...'. I think this is just a funny case of guessing that "{ bareword" begins an expression, not a block, but it dies before even noticing the missing , after }. Disambiguating it as `map {; use strict; } @ARGV` works fine. -- Online Fortune Cookie Search	[reply] [d/l] [select]
Re^2: statement vs. block? by ikegami (Patriarch) on Apr 13, 2008 at 05:28 UTC
Here, all loop constructs introduces a scope for the expression just as they would if it was a block. if however doesn't. What `if`? `>perl -MO=Deparse -e"local $If = 'local' if 1;" local $If = 'local'; -e syntax OK` [download] However, fixing the test so `if` actually exists at run-time doesn't alter the results.	[reply] [d/l] [select]