Text::Snippet - TextMate-like snippet functionality

version 0.04

This module provides TextMate-like snippet functionality via an editor-agnostic API. The snippet syntax is modeled after the snippets provided by TextMate.

    use Text::Snippet;

    my $snippet = Text::Snippet->parse($snippet_content);

	my @tabstops = $snippet->tab_stops;
	foreach my $t (@tabstops) {
		my $replacement = get_user_input();    # get user input somehow
		$t->replace($replacement) if ($user_input);
	}
	print $snippet;                           # stringify and write to STDOUT

	# alternate "cursor" interface

	my $cursor = $snippet->cursor;
	while ( my $direction = get_user_tab_direction() ) {    # forward or backward
		my $t;
		if ( $direction == 1 ) {          # tab
			$t = $cursor->next;
		} elsif ( $direction == -1 ) {    # shift-tab
			$t = $cursor->prev;
		} else {
			last;                         # bail
		}
		next if ( !$t );

		# get (zero-based) cursor position relative to the beginning of the snippet
		my($line, $column) = $cursor->current_position;

		my $replacement = get_user_input();
		$t->replace($replacement);
	}
	print $snippet; # stringify snippet and write to STDOUT

* Plain text

The simplest snippet is just plain text with no tab stops and is returned verbatim to the caller.

* Simple tab stops

Tab stops are indications for where the cursor should be placed after the user inserts a snippet. Simple tab stops are simply a dollar sign followed by a digit. The special $0 tab stop is terminal and is where the cursor will end up when the user has progressed through all other tab stops defined by the snippet. If no $0 tab stop is indicated, one is added by default right after the final character of the snippet. A simple "if" snippet (two explicit tab stops plus an implicit terminal after the closing brace of the if block):

	if ($1) {
		$2
	}

* Tab stops with defaults

Sometimes a snippet may provide a default value to the user to make the snippet easier to flesh out. These types of tab stops look like so:

	while( my(\$${1:key}, \$${2:value}) = each(%${3:hash}) {
		$0
	}

While navigating through the tab stops, the first three positions will provide default values ("key", "value" and "hash" respectively). The terminal tab stop will leave the cursor in the body of the while block.

* Tab stops with mirroring

Sometimes you may want the value the user entered in one tab stop to be copied to another. This (in TextMate lingo) is called mirroring. This is very simple to do, just use the same index on more than one tab stop and the content entered in the first will automatically be used in the others. A rather contrived example:

	foreach my \$${1:item} (@${2:array}) {
		print "$${1}\n";
	}

All occurences of the first tab stop (the loop variable and in the print statement) will have the same value (defaulting to "item").

* Transforming tab stops

The most advanced type of tab stop allows you to modify the entered value on the fly using a regular expression. For instance, if you like to use getFoo and setFoo accessors with Moose, you might use the following snippet:

	has ${1:propertyName} => (
		is => '${2:rw}',
		isa => '${3:Str}',
		reader => 'get${1/./\u$0/}),
		writer => 'set${1/./\u$0}),
	);

If the user leaves all the defaults, the output of this snippet would be:

	has propertyName => (
		is => 'rw',
		isa => 'Str',
		reader => 'getPropertyName',
		writer => 'setPropertyName'
	);

Another example would be a helper snippet for creating simple HTML tags:

	<${1:a}>${2}</${1/\s.*//}>

The transformer on the mirrored tab stop essentially will truncate anything starting with the first whitespace character entered by the user. If the user enters a href="http://search.cpan.org" as the first replacement value, the mirrored tab stop will have a replacement of just a.

This is the main entry point into this module's functionality. It takes a single argument, the content of the snippet that conforms to the syntax described above.

Obviously, gets the full content of the snippet as it currently exists. This object is overloaded as well so simply printing the object or including it inside double quotes will have the same effect.

Returns an ArrayRef that makes up the entire content of the snippet. Depending on the source of the snippet, some of these items may be literal scalars (representing static content) and others may be Text::Snippet::TabStop objects that represent the user-enterable portions of the snippet.

This returns the original source as it was passed to "parse"

This returns an ArrayRef of Text::Snippet::TabStop objects that represent the user-enterable portions of the snippet. These are ordered by the tab stop's index with the zero-th index coming last.

This method creates a Text::Snippet::TabStop::Cursor object for you which allows the caller to traverse a series of tab stops in a convenient fashion.

Please report any bugs or feature requests to bug-text-snippet at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Text-Snippet. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

You can find documentation for this module with the perldoc command.

    perldoc Text::Snippet

You can also look for information at:

* RT: CPAN's request tracker

http://rt.cpan.org/NoAuth/Bugs.html?Dist=Text-Snippet

* AnnoCPAN: Annotated CPAN documentation

http://annocpan.org/dist/Text-Snippet

* CPAN Ratings

http://cpanratings.perl.org/d/Text-Snippet

* Search CPAN

http://search.cpan.org/dist/Text-Snippet/

  Brian Phillips <bphillips@cpan.org>

This software is copyright (c) 2010 by Brian Phillips.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.