NAME
    Devel::Declare::Parser - Higher level interface to Devel-Declare

DESCRIPTION
    Devel-Declare-Parser is a higher-level API sitting on top of
    Devel::Declare. It is used by Devel::Declare::Exporter to simplify
    exporting of Devel::Declare magic. Writing custom parsers usually only
    requires subclassing this module and overriding a couple methods.

DOCUMENTATION
    Devel::Declare::Interface
        This is the primary interface for those who want to use
        Devel-Declare-Parser magic, and don't wantto use Exporter-Declare.

    Devel::Declare::Parser
        This Document covers the API for Devel::Declare::Parser. This API is
        a useful reference when writing or modifying a custom parser.

SYNOPSIS
        package Devel::Declare::Parser::MyParser;
        use strict;
        use warnings;

        use base 'Devel::Declare::Parser';
        use Devel::Declare::Interface;

        # Create an accessor (See INTERNALS WARNING below)
        __PACKAGE__->add_accessor( 'my_accessor' );

        # Register the parser for use.
        Devel::Declare::Interface::register_parser( 'myparser' );

        # Override the rewrite() method to take the parsed bits (parts) and put the
        # ones you want into new_parts.
        sub rewrite {
            my $self = shift;

            my $parts = $self->parts;

            $new_parts = $self->process_parts( $parts );

            $self->new_parts( $new_parts );
            1;
        }

        1;

OVERVIEW
    This is a brief overview of how a parser is used.

  WORKFLOW
    Parser is constructed
        Name, Declarator, and Offset are provided by Devel::Declare.

    The process() method is called
        The process method calls all of the following in sequence, if any
        returns false, process() will return.

        pre_parse()
                Check if we want to process the line at all.

        parse() Turn the line into 'parts' (see below).

        post_parse()
                Hook, currently does nothing.

        rewrite()
                Hook, currently takes all the arguments between the
                declarator and the codeblock/semicolon (which have been
                turned into 'parts' structures in the parts() attribute) and
                puts them into the new_parts() attribute.

                This is usually the method you want to override.

        write_line()
                Opens, fills in, and closes the line as a string, then
                rewrites the actual line using Devel::Declare.

        edit_line()
                Hook, currently does nothing.

  "PARTS"
    'Parts' are datastructures created by the parse() method. Every argument
    on the line (space separated) up until an opening curly brace ({) or a
    semicolon (;) will be turned into a part. Here are the parts to expect:

    Parts will either be a plain string, or an arrayref containing a string
    and the quote character used to define the string. "String" or [
    "String", '"' ]. Variables and operators (excluding those containing
    only string characters) are typically the only parts left in a plain
    string form.

    See the format_parts() method for an easy way to get what you need from
    a 'part' datastructure.

    Bareword or Package Name
        A barword name is anythign that starts with [a-zA-z] and contains
        only alpha-numerics plus underscore. It is also not quoted. Examples
        include my_name, something5, etc.

        The structure will be an arrayref, the first element will be the
        string form of the bareword name, the second element will be undef.

        Example:

            # my_keyword My::Package;
            $part = [
                'My::Package',
                undef,
            ];

            # my_keyword some_name;
            $part = [
                "some_name",
                undef,
            ];

    Quoted or Enclosed Element
        A quoted or enclosed element includes strings quoted with single or
        double quotes, and text contained within opening and closing
        brackets, braces or parens (excluding the curly brace '{').

        Example Structures:

            # my_keyword "double quoted string";
            $part = [
                'double quoted string',
                '"',
            ];

            # my_keyword 'single quoted string';
            $part = [
                'double quoted string',
                '"',
            ];

            # my_keyword ... ( a => 'b', c => 'd' );
            $part = [
                " a => 'b', c => 'd' ",
                "(",
            ];

    Variable or Operator
        Anything starting with a non-alphanumeric, non-quoting character
        will be placed as-is (not interpolated) into a string. This catches
        most variables and operators, the exception are alpha-numeric
        operators such as 'eq', 'gt', 'cmp', etc. Eventually I plan to add
        logic to catch all oeprators, but it appears I will have to
        hard-code them.

            # my_keyword $variable
            $part = '$variable';

            # my_keyword <=>
            $part = '<=>';

  EVENTUAL OUTPUT
    Parser is designed such that it will transform any and all uses of your
    keyword into proper function calls.

    That is this:

        function x { ... }

    Will become this:

        function( 'x', sub { ... });

    Note Parser does not read in the entire codeblock, rather it injects a
    statement into the start of the block that uses a callback to attach the
    ');' to the end of the statement. This is per the documentation of
    Devel::Declare. Reading in the entire sub is not a desirable scenario.

DEVEL-DECLARE-PARSER API
  INTERNALS WARNING
    Parser objects are blessed arrays, not hashrefs.

    If you want to create a new accessor use the add_accessor() class
    method. It will take care of assigning an unused array element to the
    attribute, and will create a read/write accessor sub for you.

        __PACKAGE__->add_accessor( 'my_accessor' );

    There are many public and private methods on the parser base class. Only
    the public methods are fully documented. Be sure to refer often to the
    list of private methods at the end of this document, accidently
    overriding a private method could have devestating consequences.

  CLASS METHODS
    $class->new( $name, $declarator, $offset )
        The constructor, "DO NOT OVERRIDE THIS!"

    $class->DEBUG($bool)
        Turn debugging on/off. This will output the line after it has been
        modified, as well as some context information.

        NOTE: This has a global effect, all parsers will start debugging.

  UTILITY METHODS
    bail( @messages )
        Like croak, dies providing you context information. Since any death
        occurs inside the parser, carp provides useless information.

    diag( @message )
        Like carp, warns providing you context information. Since the warn
        occurs inside the parser carp provides useless information.

    end_quote($start_char)
        Find the end-character for the provide starting quote character. As
        in '{' returns '}' and '(' returns ')'. If there is no counter-part
        the start character is returned: "'" returns "'".

    filename()
        Filename the rewrite is occuring against.

    linenum()
        Linenum the rewrite is occuring on.

    format_part()
        Returns the stringified form of a part datastructure. For variables
        and operators that is just the item itself as a string. For
        barewords or package names it is the item itself with single quotes
        wrapped around it. For quoted items it is the string wrapped in its
        proper quoting characters. If a second parameter is provided (and
        true) no single quotes will be added to barewords.

  ACCESSORS
    These are the read/write accessors used by Parser. Not all of these act
    on an array element, some will directly alter the current line.

    line()
        This will retrieve the current line from Devel-Declare. If given a
        value, that value will be set as the current line using
        Devel-Declare.

    name()
        Name of the declarator as provided via the parser.

    declarator()
        Name of the declarator as provided via the Devel-Declare.

    original_offset()
        Offset on the line when the parsing was started.

    offset()
        Current line offset.

    parts()
        Arrayref of parts (may be undef)

    new_parts()
        Arrayref of new parts (may be undef)

    end_char()
        Will be set to the character just after the completely parsed line
        (usually '{' or ';')

    prototype()
        Used internally for prototype tracking.

    contained()
        True if the parser determined this was a contained call. This means
        your keyword was followed by an opening paren, and the statement
        ended with a closing paren and semicolon. By default Parser will not
        modify such lines.

  OVERRIDABLE METHODS
    These are methods you can, should, or may override in your baseclass.

    quote_chars()
        Specify the starting characters for quoted strings. (returns a list)

    end_chars()
        Characters to recognise as end of statement characters (';' and '{')
        (returns a list)

    inject()
        Code to inject into functions enhanced by this parser.

    pre_parse()
        Check if we want to process the line at all.

    parse()
        Turn the line into 'parts'.

    post_parse()
        Hook, currently does nothing.

    rewrite()
        Hook, currently takes all the arguments between the declarator and
        the codeblock/semicolon (which have been turned into 'parts'
        structures in the parts() attribute) and puts them into the
        new_parts() attribute.

        This is usually the method you want to override.

    write_line()
        Opens, fills in, and closes the line as a string, then rewrites the
        actual line using Devel::Declare.

    edit_line()
        Hook, currently does nothing.

    open_line()
        Usually returns '('. This is how to start a line following your
        keyword

    close_line()
        End the line, this means either re-inserting the opening '{' on the
        codeblock, along with any injections, or returning ');'

  POSITION TRACKING
    advance( $num_chars )
        Advances the offset by $num_chars.

    skip_declarator()
        Skips the declarator at the start of the line.

    skipspace()
        Advances the offset past any whitespace.

  LINE EXAMINATION (NON-MODIFYING)
    These are used by pre_parse() to examine the line prior to any
    modification.

    is_contained()
        True if the line is of the format:

            keyword( ... );

    is_arrow_contained()
        True if the line is of the format:

            keyword word_or_string => ( ... );

    is_defenition()
        True if the line matches the regex m/sub[\s\n]+$name/sm

  PART EXAMINATION
    These are methods that let you investigate the parts already parsed and
    placed in the parts() attribute.

    has_non_string_or_quote_parts()
        Returns a list of parts that are not strings, quotes, or barewords.

    has_string_or_quote_parts()
        Returns a list of parts that are strings, quotes, or barewords.

    has_keyword( $word )
        Check for a keyword in the parts

    has_comma()
    has_fat_comma()

  LINE EXAMINATION (MODIFYING)
    This examines the line returning part structures and removing elements
    from the line each time they are called.

    strip_item()
    strip_length()
    strip_remaining_items()

  LOOKING AHEAD
    These methods help the parser determine what comes next in a line. In
    most cases these are non-modifying.

    peek_is_block()
    peek_is_end()
    peek_is_other()
    peek_is_quote()
    peek_is_word()
    peek_item()
    peek_item_type()
    peek_num_chars()
    peek_other()
    peek_quote()
    peek_remaining()
    peek_word()

  PRIVATE METHODS
    Do not use these, and definitely do not override them in a subclass.

    _block_end_injection()
    _debug()
    _edit_block_end()
    _item_via_()
    _linestr_offset_from_dd()
    _move_via_()
    _peek_is_package()
    _peek_is_word()
    _quoted_from_dd()
    _scope_end()
    _stash()
    _unstash()

AUTHORS
    Chad Granum exodist7@gmail.com

COPYRIGHT
    Copyright (C) 2010 Chad Granum

    Devel-Declare-Parser is free software; Standard perl licence.

    Devel-Declare-Parser is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the license for
    more details.