Structure and Interpretation of Computer Programmers

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Wednesday, June 11, 2008

WWDC aside

None of Perl, Cocoa or some weird XML toolkit came up with the “simple things simple, complex things possible” quote.

posted by Graham Lee at 21:40  

Thursday, March 15, 2007


When most perl developers (I believe there still are one or two in existence) talk of the "cool one-liner" that they wrote, what they actually mean is that they grabbed a crapload of packages from CPAN, invoked a few use directives and then, finally, could write one line of their own code which happens to invoke a few hundred lines of someone else’s code, which they have neither read nor tested.

Modulo testing, my short script (below) to convert mbox mailboxes to maildirs is exactly like that. While it has three lines of meat, these call upon the (from what I can tell, fantastic) Mail::Box module to do the heavy lifting. That package itself is less svelte, with 775 lines of perl. Which is the interface to a C bundle, which is (single-arch) 92k. But never mind, I still wrote a three-liner ;-)

#!/usr/bin/perl -w

use strict;

use Mail::Box::Manager;

@ARGV = ("~/mail", "~/Maildir") unless @ARGV;

# open the existing (mbox) folders
my $mgr = new Mail::Box::Manager;
my ($srcPath, $dstPath) = @ARGV;
# expand tildes and stuff
$srcPath = glob $srcPath;
$dstPath = glob $dstPath;

opendir MBOXDIR, $srcPath or die "couldn't open source path: $!";

foreach my $file (grep !/^./, readdir MBOXDIR)
my $mbox = $mgr->open(folder => "$srcPath/$file",
folderdir => "$srcPath");
# open a maildir to store the result
my $maildir = $mgr->open(folder => "$dstPath/$file",
type => "Mail::Box::Maildir",
access => 'rw',
folderdir => "$dstPath",
create => 1);

$mgr->copyMessage($maildir, $mbox->messages);
posted by Graham Lee at 17:32  

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