Jeff Dutton > Parse-RandGen > Parse::RandGen::Production

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NAME ^

Parse::RandGen::Production - Conditions for rule to match (and the action to take if it does)

DESCRIPTION ^

A Production defines a set of Conditions that must be satisfied for a Rule to match input text. The Production consists of an ordered list of Conditions (subrules, literals, and regexps) that must sequentially match for the Production to match.

A rule matches if any one of its Productions match the input text. In BNF notation, the relationship of Rules and Productions is:

  rule1:         production1
               | production2
               | production3

For example:

  perlFuncCall:  /&?/ identifier '(' argument(s?) ')'
               | scalar '->' identifier '(' argument(s?) ')'

The two Productions in this example could respectively match:

    "func()",  "func(x, y)",  or "&func(x)"
    "$obj->member()"

The first Production in this example is a list of:

    Parse::RandGen::Production->new(
        cond => qr/&?/,         # Regexp  Condition - 0 or 1 '&' characters
        cond => "indentifier",  # Subrule Condition - exactly 1 "identifier" rule
        cond => q{'('},         # Literal Condition - single '(' character
        cond => "argument(s?)", # Subrule Condition - 0 or more "argument" rules
        cond => ')',            # Literal Condition - single ')' character
    );

Be aware of the greediness of the underlying parsing mechanism. If a production consists of subsequent conditions, such that the earlier ones can satisfy later ones, then they must be combined into one condition represented by a regular expression. Regular expressions can manage the greediness of their matching in order to get the desired effect.

    identifier:        /\w*/  /\d/    # The second condition can be met by the first

METHODS ^

new

Creates a new Production. The arguments are all named pairs. The only required pair is "cond" => condition. The Production can be named with the "name" argument (accessed by the name() accessor).

Any unknown named arguments are treated as user-defined fields. They are stored in the Condition hash ($cond->{}).

  Parse::RandGen::Production->new( name => 'request',
                                   cond => q{'Request:'},
                                   cond => qr/(\s*\w+\s*[,$]+)/ );
rule

Returns the Parse::RandGen::Rule object that this Production belongs to.

grammar

Returns the Parse::RandGen::Grammar object that this Production belongs to (returns rule()->grammar()).

check

Checks the Production to verify that all subrules can be found in the RandGen.

conditions

Returns a list with the Production's Conditions.

SEE ALSO ^

Parse::RandGen, Parse::RandGen::Rule, and Parse::RandGen::Condition

AUTHORS ^

Jeff Dutton

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