in reply to Re: Re: Re: Some suggestions on coding style - a chance to critique
in thread Some suggestions on coding style - a chance to critique

using constant is a very good thing to do. However, if you don't know what constant is doing, you can be very surpsised. 
use constant LOG_DIRECTORY => '/foo/bar/baz';

# Equivalent to

sub LOG_DIRECTORY () { '/foo/bar/baz' }

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The most obvious problem is interpolation in double-quoted strings.

Similarly, you can't use LOG_DIRECTORY as the key to a hash, because it's not a C-style preprocessor declaration, but a function declaration.

Just, be careful and know what is happening under the hood.

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Re5: Some suggestions on coding style - a chance to critique
by blakem (Monsignor) on Jul 01, 2002 at 21:03 UTC
    Doh! Nevermind....

    I can see the interpolation problem, but whats this about not using a constant as a hash key? 

    #!/usr/bin/perl -w
use strict;

use constant LOG_DIRECTORY => '/foo/bar/baz';

my %hash;
$hash{LOG_DIRECTORY} = 'happy';

print "log directory ${\LOG_DIRECTORY} is $hash{LOG_DIRECTORY}\n";

__END__
produces:

log directory /foo/bar/baz is happy

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    -Blake

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[d/l]
Re: Re4: Some suggestions on coding style - a chance to critique
by Anonymous Monk on Jul 01, 2002 at 22:14 UTC
    Try printing out the keys of %hash. You just assigned the value "happy" to the key "LOG_DIRECTORY". To use the constant LOG_DIRECTORY as the key you need to explicitly use it as a function.
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