Class: RLSM::RE::Parser

Inherits:
Object
  • Object
show all
Extended by:
ParserHelpers
Defined in:
lib/rlsm/regexp_parser.rb

Overview

:nodoc:

Constant Summary

Constants included from ParserHelpers

RLSM::RE::ParserHelpers::CloseBracket, RLSM::RE::ParserHelpers::EmptyWordSymbol, RLSM::RE::ParserHelpers::LetterRegexp, RLSM::RE::ParserHelpers::OpenBracket, RLSM::RE::ParserHelpers::StarSymbol, RLSM::RE::ParserHelpers::UnionSymbol

Class Method Summary collapse

Methods included from ParserHelpers

close_bracket?, empty_set?, empty_symbol?, empty_word?, letter?, open_bracket?, single_letter?, star?, star_symbol?, union?, union_symbol?

Class Method Details

.[](string) ⇒ Object 



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# File 'lib/rlsm/regexp_parser.rb', line 115

def self.[](string)
  index = -1
  input = string.gsub(/\s+/,'').scan(/./).map do |char| 
    letter?(char) ? Position.new(char,index += 1) : Position.new(char)
  end

  if unbalanced_brackets?(input)
    raise RLSM::Error, "Parse Error: Unbalanced brackets."
  end
  
  parse(input)      
end

.parse(input) ⇒ Object 



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# File 'lib/rlsm/regexp_parser.rb', line 128

def self.parse(input)
  input = remove_surrounding_brackets(input)

  if empty_set?(input)
    EmptySet[]
  elsif empty_word?(input)
    EmptyWord[]
  elsif single_letter?(input)
    Prim[ input.first ]      
  elsif star?(input)
    create_star_node( input )
  elsif union?(input)
    create_union_node(input)
  else #must be a concat
    create_concat_node(input)
  end
end