free_mutant/lib/mutant/expression.rb

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module Mutant
# Abstract base class for match expression
class Expression
include AbstractType, Adamantium::Flat
fragment = /[A-Za-z][A-Za-z\d_]*/.freeze
SCOPE_NAME_PATTERN = /(?<scope_name>#{fragment}(?:#{SCOPE_OPERATOR}#{fragment})*)/.freeze
SCOPE_SYMBOL_PATTERN = '(?<scope_symbol>[.#])'.freeze
private_constant(*constants(false))
# Syntax of expression
#
# @return [String]
abstract_method :syntax
# Match length with other expression
#
# @param [Expression] other
#
# @return [Fixnum]
def match_length(other)
if eql?(other)
syntax.length
else
0
end
end
# Test if expression is prefix
#
# @param [Expression] other
#
# @return [Boolean]
def prefix?(other)
!match_length(other).zero?
end
# Try to parse input into expression of receiver class
#
# @param [String] input
#
# @return [Expression]
# when successful
#
# @return [nil]
# otherwise
def self.try_parse(input)
match = self::REGEXP.match(input)
return unless match
names = anima.attribute_names
new(Hash[names.zip(names.map(&match.method(:[])))])
end
end # Expression
end # Mutant