On 2010.04.13 23:17, Kenneth Wolcott wrote:
> Hi;
>
> On Tue, Apr 13, 2010 at 19:54, Uri Guttman <[email protected]> wrote:
>>>>>>> "JG" == Jim Gibson <[email protected]> writes:
>>
>> JG> On 4/13/10 Tue Apr 13, 2010 4:35 PM, "Mimi Cafe"
>> <[email protected]>
>> JG> scribbled:
>>
>> >> I think this will work, but is it elegant.?
>>
>> JG> Yes, it will work, and yes, it is elegant, as long as it encapsulates
>> the
>> JG> logic that is required by your program.
>>
>> i disagree that it is elegant. too often if/else lists are not
>> needed. many can be replaced by dispatch tables. if one of the clauses
>> does just a return or next/last that can be replaced with a modifier or
>> shorter statement. without ANY serious work, i have over 10k lines of
>> perl code in one system with about 10 else's and maybe 3 elsif's. it
>> just is a matter of knowing how to manage flow control well and you
>> rarely need else's.
>>
>> uri
>
> I really like the switch statement (native in Perl v5.10) over
> anything more complicated than one if/else clause.
I agree with Uri. Even switch statements can be cumbersome depending on
how many cases you have. I believe that (in the majority of cases)
dispatch tables are far more effective, easy to read (like a table of
contents) and maintainable (ie. very easy to add to without having to
worry about placement).
#!/usr/bin/perl
use warnings;
use strict;
my $dt = {
simple => sub { print "Simple, anon sub inline\n" },
easy => sub { my $num = 1; print $num*2 ."\n";},
complex => \&complex, # coderef to external sub,
};
sub complex {
my $num = shift;
# ... do a bunch of stuff
print "$num\n";
}
# call them
$dt->{ simple }();
$dt->{ easy }();
$dt->{ complex }( 5 );
Steve
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