On Sep 22, John W. Krahn said:
The if statement modifier is just another way to write a logical and statement:
$ perl -MO=Deparse -e' display_nothing() if $match_type eq q/none/ '
display_nothing() if $match_type eq 'none';
-e syntax OK
$ perl -MO=Deparse -e' $match_type eq q/none/ and display_nothing() '
display_nothing() if $match_type eq 'none';
-e syntax OK
$ perl -MO=Deparse -e' $match_type eq q/none/ && display_nothing() '
display_nothing() if $match_type eq 'none';
-e syntax OK
An important difference, though, is that the if statement modifier takes
an expression and produces a statement, so you can't store its return
value somewhere. That is,
$result = (do_this() if that());
is a syntax error. Not so in the case of '&&' and 'and':
$result = (that() and do_this());
$result = (that() && do_this());
However, you can turn any statement into an expression by using do { }
around the statement:
$result = do { do_this() if that(); };
--
Jeff "japhy" Pinyan % How can we ever be the sold short or
RPI Acacia Brother #734 % the cheated, we who for every service
http://www.perlmonks.org/ % have long ago been overpaid?
http://princeton.pm.org/ % -- Meister Eckhart
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