NAME YAML::Tiny - Read/Write YAML files with as little code as possible PREAMBLE The YAML specification is huge. Like, really huge. It contains all the functionality of XML, except with flexibility and choice, which makes it easier to read, but with a full specification that is more complex than XML. The pure-Perl implementation YAML costs just over 4 megabytes of memory to load. Just like with Windows .ini files (3 meg to load) and CSS (3.5 meg to load) the situation is just asking for a YAML::Tiny module, an incomplete but correct and usable subset of the functionality, in as little code as possible. Now, given the YAML features one would need in order to have something that is usable for things like META.yml and simple configuration files, there is still enough complexity that I'm not sure if it is even possible to do a YAML::Tiny module. So I'm going to impose some ground rules before I start. Like the other "::Tiny" modules, YAML::Tiny will have no non-core dependencies, not require a compiler, and be back-compatible to at least perl 5.005_03, and ideally 5.004. And I'm setting a hard-limit of 400k of memory to load it (1/10th of YAML.pm). I plan to implement features starting at the most common and working towards the least common, but if we hit 400k limit then we stop until we can find a way to squish the same functionality into less code and free some up. At this point, other than unquoted scalars, arrays, hashes and ASCII, I promise nothing. So do not use this module for anything other than experimentation. It's only just getting started. SYNOPSIS ############################################# # In your file --- rootproperty: blah section: one: two three: four Foo: Bar empty: ~ ############################################# # In your program use YAML::Tiny; # Create a YAML file my $yaml = YAML::Tiny->new; # Open the config $yaml = YAML::Tiny->read( 'file.yml' ); # Reading properties my $root = $yaml->[0]->{rootproperty}; my $one = $yaml->[0]->{section}->{one}; my $Foo = $yaml->[0]->{section}->{Foo}; # Changing data $yaml->[0]->{newsection} = { this => 'that' }; # Add a section $yaml->[0]->{section}->{Foo} = 'Not Bar!'; # Change a value delete $yaml->[0]->{section}; # Delete a value or section # Add an entire document $yaml->[1] = [ 'foo', 'bar', 'baz' ]; # Save the file $yaml->write( 'file.conf' ); DESCRIPTION YAML::Tiny is a perl class to read and write YAML-style files with as little code as possible, reducing load time and memory overhead. Most of the time it is accepted that Perl applications use a lot of memory and modules. The ::Tiny family of modules is specifically intended to provide an ultralight and zero-dependency alternative to the standard modules. This module is primarily for reading human-written files (like config files) and generating very simple human-readable files. Note that I said human-readable and not geek-readable. The sort of files that your average manager or secretary should be able to look at and make sense of. YAML::Tiny does not generate comments, it won't necesarily preserve the order of your hashes, and it will normalise if reading in and writing out again. It only supports a very basic subset of the full YAML specification. Usage is targetted at files like Perl's META.yml, for which a small and easily-embeddable module would be highly useful. Features will only be added if they are human readable, and can be written in a few lines of code. Please don't be offended if your request is refused. Someone has to draw the line, and for YAML::Tiny that someone is me. If you need something with more power move up to YAML (4 megabytes of memory overhead) or YAML::Syck (275k, but requires libsyck and a C compiler). To restate, YAML::Tiny does not preserve your comments, whitespace, or the order of your YAML data. But it should round-trip from Perl structure to file and back again just fine. METHODS new The constructor "new" creates and returns an empty "YAML::Tiny" object. read $filename The "read" constructor reads a YAML file, and returns a new "YAML::Tiny" object containing the contents of the file. Returns the object on success, or "undef" on error. When "read" fails, "YAML::Tiny" sets an error message internally you can recover via "YAML::Tiny->errstr". Although in some cases a failed "read" will also set the operating system error variable $!, not all errors do and you should not rely on using the $! variable. read_string $string; The "read_string" method takes as argument the contents of a YAML file (a YAML document) as a string and returns the "YAML::Tiny" object for it. write $filename The "write" method generates the file content for the properties, and writes it to disk to the filename specified. Returns true on success or "undef" on error. write_string Generates the file content for the object and returns it as a string. errstr When an error occurs, you can retrieve the error message either from the $YAML::Tiny::errstr variable, or using the "errstr()" method. FUNCTIONS YAML::Tiny implements two functions to add compatibility with the YAML API. These should be a drop-in replacement, except that YAML::Tiny will not export functions by default, and so you will need to explicitly import the functions. Dump my $string = Dump(list-of-Perl-data-structures); Turn Perl data into YAML. This function works very much like Data::Dumper::Dumper(). It takes a list of Perl data strucures and dumps them into a serialized form. It returns a string containing the YAML stream. The structures can be references or plain scalars. Load my @documents = Load(string-containing-a-YAML-stream); Turn YAML into Perl data. This is the opposite of Dump. Just like Storable's thaw() function or the eval() function in relation to Data::Dumper. It parses a string containing a valid YAML stream into a list of Perl data structures. SUPPORT Bugs should be reported via the CPAN bug tracker at AUTHOR Adam Kennedy SEE ALSO YAML, YAML::Syck, Config::Tiny, CSS::Tiny, COPYRIGHT Copyright 2006 - 2007 Adam Kennedy. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module.