Re: [PATCH] git-mv.perl: use stderr for error output and cleanup
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>
> BTW, I never understood the usefulness of Statement Modifiers.
> Even reading the examples in perlsyn.pod:
>
> print "Basset hounds got long ears" if length $ear >= 10;
> go_outside() and play() unless $is_raining;
>
> seeing "do these things" upfront and then realize "ah, but that
> is done only when this holds true", interrupts the flow of
> understanding while reading a program by somebody else [*1*].
Here's what "Programming Perl" by O'Reilly (third edition, somewhere around page 604) has to say about it: ---%<---%<---%<--- *) Do things the most readable way. For instance:
open(FOO, $foo) or die "Can't open $foo: $!";
is better than
die "Can't open $foo: $!" unless open(FOO, $foo);
because the second way hides the main point of the statement in a modifier. ---%<---%<---%<---
Considering the book was co-authored by Larry Wall, I'd say that's as good as an apology.
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> It is worse if the Statement Modifier is a loop control.
>
> (flamebait) Compound Statements take BLOCK and people who want
> to do a one-liner could not do so without braces. I've always
> thought Statement Modifies as a lame workaround for that
> problem.
>
Most things can be done without braces, so long as one doesn't spell out the 'if'.
$opt_h and usage();
-d $directory or mkdir($directory);
is perfectly valid perl. This way of writing it is familiar enough for shell-scripters. Hardcore C-programmers will look twice when they see a line that so obviously looks completely wrong and will almost certainly, with some revulsion, understand it.
--
Andreas Ericsson andreas.ericsson@op5.se
OP5 AB www.op5.se
Tel: +46 8-230225 Fax: +46 8-230231
Alex Riesen
