Low-Maintenance Perl

low maintenance perl
“optimizing for an easy life”

perrin harkins
plus three

the fud

“i would never use perl for a large project.”
“perl is unmaintainable.”
“perl is writeonly.”

i shouldn't have to tell you this

use strict;
use warnings;
perltidy

know your audience

“code is always read more times than it is
written.”
andy hunt

choosing a dialect

don't use something complex when
something simple will work.

choosing a dialect

don't do things in a magical way when an
explicit way will work.

choosing a dialect

don't make your code complex just so you
can get a certain syntax.

choosing a dialect

fetch("search.cpan.org") > my @cont;

is equivalent to

my $scraper = FEAR::API>fear();
my $page = $scraper>fetch("search.cpan.org");
push my @cont, $page>document>as_string;

choosing a dialect

follow conventions when you can.

choosing a dialect

which scans faster?

s{foo}{bar}g;

s/foo/bar/g;

choosing a dialect

don't use an obscure language feature
when a common one will work.

choosing a dialect

dragonchild's law:
"if i have to ask if something is possible on
perlmonks, i probably should rethink my
design."

obscure features

“We redesigned the protocol several times until we had a
protocol that performed well. However,
the resulting protocol was too complex and depended on the
behavior of Chubby features that were seldom exercised by
other applications. We discovered that we were spending an
inordinate amount of time debugging obscure corner cases,
not only in Bigtable code, but also in Chubby code. Eventually,
we scrapped this protocol and moved to a newer simpler
protocol that depends solely on widelyused Chubby features.”
Google Bigtable Paper

obscure features

example of a changing feature:

my $foo = 1 if $bar;

never

punctuation variables

my $text = do { local $/ = undef; <$fh>; };

never

import functions that don't import

use Catalyst qw/Debug/;

use Catalyst ();

never

function prototypes

sub do_it (&@) {
blah blah blah
}

never

indirect object syntax

new Class #no

Class>new() #yes

never

alternative inheritance schemes

never

reblessing existing objects

bless, $object, 'Some::Other::Class';

never

objects that aren't hashes

(but maybe Object::InsideOut)

overloading

use Exception::Class
qw(MyProject::BadKarma);

# in some method, the exception is triggered
MyProject::BadKarma>throw();

# in the caller, we catch it with eval
if ($@ and $@>isa('MyProject::BadKarma')) {

never

multiple packages in one file

never

the constant pragma

use constant TEA => 'Darjeeling';
%beverages = (TEA => 1);

our $TEA = 'Darjeeling';
%beverages = ($TEA => 1);

never

tied variables

tie(%h,’SDBM_File’, ’filename’,...);

$h{'foo'} = 1;

rarely

wantarray

@books = Book>search(author => $author)
|| die "book not found";

sometimes

sub attributes

sub foo : attribute {

sometimes

code references

sometimes

chained map/grep

sometimes

ternary operator

my $foo = $bar ? 'yes' : 'no';

questions you might have

doesn't this take all the fun out of
programming?


won't this make your code longer?


but AUTOLOAD is awesome!


why don't you just use Java?

beyond the code

●
configuration management
●
version control with branches

beyond the code

●
tests can save your life
●
Test::Class can save your tests
●
smolder,
http://sourceforge.net/projects/smolder/

Low-Maintenance Perl

More Related Content

What's hot (18)

Similar to Low-Maintenance Perl (20)

More from Perrin Harkins (9)

Recently uploaded (20)

Low-Maintenance Perl