Grammar::Formal - Object model to represent formal BNF-like grammars
use Grammar::Formal; my $g = Grammar::Formal->new; my $s1 = Grammar::Formal::CaseSensitiveString->new(value => "a"); my $s2 = Grammar::Formal::CaseSensitiveString->new(value => "b"); my $choice = Grammar::Formal::Choice->new(p1 => $s1, p2 => $s2); $g->set_rule("a-or-b" => $choice);
This module provides packages that can be used to model formal grammars with production rules for non-terminals and terminals with arbitrary operators and operands. The idea is to have a common baseline format to avoid transformations between object models. Currently it has enough features to model IETF ABNF grammars without loss of information (minor details like certain syntax choices notwithstanding). All packages use Moose.
Grammar::Formal::Pattern # Base package for all operators and operands has rw user_data # Simple extension point has ro parent # parent node if any + Grammar::Formal::Binary # Base package for operators with 2 children has ro p1 # first child has ro p2 # second child + Grammar::Formal::Group # concatenation + Grammar::Formal::Choice # alternatives + Grammar::Formal::OrderedChoice # ... with preference + Grammar::Formal::Unary # Base package for operators with 1 child has ro p # the child pattern + Grammar::Formal::ZeroOrMore # zero or more + Grammar::Formal::OneOrMore # one or more + Grammar::Formal::SomeOrMore # min-bounded has ro min # minimum number of occurences + Grammar::Formal::BoundedRepetition # bound repetition has ro min # minimum number of occurences has ro max # maximum number of occurences + Grammar::Formal::Rule # grammar production rule has ro name # name of the non-terminal symbol + Grammar::Formal::Reference # Named reference to a non-terminal symbol has ro ref # name of the referenced non-terminal can expand # returns the associated ::Rule or undef + Grammar::Formal::Grammar # A grammar pattern with named rules has ro rules # Hash mapping rule names to ::Rules has ro start # optional start symbol can set_rule($name, $value) # set rule $name to ::Rule $rule + Grammar::Formal::CaseSensitiveString # Case-sensitive sequence of characters has ro value # Text string this represents + Grammar::Formal::AsciiInsensitiveString # Sequence of characters that treats [A-Z] like [a-z] has ro value # Text string + Grammar::Formal::ProseValue # Free form text description, as in IETF ABNF grammars has ro value # Prose + Grammar::Formal::Range # Range between two integers (inclusive) has ro min # first integer in range has ro max # last integer in range + Grammar::Formal::CharClass # Set of integers has ro spans # a Set::IntSpan object can from_numbers(@ints) # static constructor
Surely there is a better way to automatically generate better POD?
Copyright (c) 2014 Bjoern Hoehrmann <email@example.com>. This module is licensed under the same terms as Perl itself.