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Re: Key-Board Interactive Perl Application

by roboticus (Canon)
on Dec 12, 2012 at 11:30 UTC ( #1008489=note: print w/ replies, xml ) Need Help??


in reply to Key-Board Interactive Perl Application

...must...resist...urge...to...post...symbolic...reference...example...

Whew! I wrote the symbolic reference example, but didn't post it. Here are a couple alternatives:

You can use brute force:

while (my $inp = <>) { $inp =~ s/^\s*(\w+)\s*$/$1/; if ($inp eq 'AB') { AB() } elsif ($inp eq 'CD') { CD() } ... etc ... else { print "Command unknown: '$inp'\n"; } }

If you're using a more modern perl the brute force method could look like:

while (my $inp = <>) { $inp =~ s/^\s*(\w+)\s*$/$1/; given ($inp) { when ('AB') { AB() } when ('CD') { CD() } ... etc ... default { print "Command unknown: '$inp'\n"; } }

However, a better method is a dispatch table. There's a little more setup work at the beginning, but as you add new command handlers, you'll find it's easier to maintain:

my %dispatch_table = ( AB => \&AB, CD => \&CD, ... etc ... ); while (my $inp = <>) { $inp =~ s/^\s*(\w+)\s*$/$1/; if (exists $dispatch_table{$inp}) { &{$dispatch_table{$inp}}(); } else { print "Command unknown: '$inp'\n"; } }

...roboticus

When your only tool is a hammer, all problems look like your thumb.


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