Dave's Brain

Browse - programming tips - compact shrink perl code

Date: 2011apr28
Updated: 2011aug4
Language: perl

Q.  How can I compact/shrink perl code?

A.  Here are some ways:

* Remove spaces

	Before:

		$hello = 'world';

	After:

		$hello='world';

* Remove newlines

	Before:

		if ($condition)
		{
			doSomething();
		}

	After:

		if ($condition) {
			doSomething();
		}

	Or:

		if ($condition) { doSomething(); }

* Ident with tabs -- not spaces.

* Remove semicolons.
Did you know that (unlike in C) semicolons are separators not statement terminators.
So every semicolon before a close brace bracket can be removed.

	Before:

		if ($condition)
		{
			doSomething();
		}

	After:

		if ($condition)
		{
			doSomething()
		}

* Invert "if" statements
This removes the need for brace brackets if you are only doing one statement.

	Before:

		if ($condition) { doSomething(); }

	After:

		doSomething() if ($condition);

* Remove quotes when using a hash

	Before:

		$is_secure = $ENV{'HTTPS'};

	After:

		$is_secure = $ENV{HTTPS};

* Use "each" for readonly loops

	http://www.google.com/search?q=perl+each

* Use "my" inside "for"

	Before:

		my $i;
		for $i (1..10) {
			say $i;
		}

	After:

		for my $i (1..10) {
			say $i;
		}

* Use "map" and "grep"

	http://www.google.com/search?q=perl+map
	http://www.google.com/search?q=perl+grep

* Use the negative pattern binding operator !~

	Before:

		if (!($string =~ m/target/)) {
			print "no match on target\n";
		}

	After:

		if ($string !~ m/target/) {
			print "no match on target\n";
		}

* There are many more ways.
But try to keep your code readable too.

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