145 lines
2.9 KiB
Ruby
145 lines
2.9 KiB
Ruby
module Mutant
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# Abstract base class for match expression
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class Expression
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include AbstractType, Adamantium, Concord::Public.new(:match)
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include Equalizer.new(:syntax)
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SCOPE_NAME_PATTERN = /[A-Za-z][A-Za-z\d_]*/.freeze
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METHOD_NAME_PATTERN = Regexp.union(
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/[A-Za-z_][A-Za-z\d_]*[!?=]?/,
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*AST::Types::OPERATOR_METHODS.map(&:to_s)
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).freeze
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SCOPE_PATTERN = /#{SCOPE_NAME_PATTERN}(?:#{SCOPE_OPERATOR}#{SCOPE_NAME_PATTERN})*/.freeze
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REGISTRY = {}
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# Error raised on invalid expressions
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class InvalidExpressionError < RuntimeError; end
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# Error raised on ambigous expressions
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class AmbigousExpressionError < RuntimeError; end
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# Initialize expression
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#
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# @param [MatchData] match
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#
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# @api private
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#
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def initialize(*)
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super
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@syntax = match.to_s
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end
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# Return syntax
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#
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# @return [String]
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#
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# @api private
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#
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attr_reader :syntax
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# Return match length for expression
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#
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# @param [Expression] other
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#
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# @return [Fixnum]
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#
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# @api private
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#
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def match_length(other)
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if eql?(other)
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syntax.length
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else
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0
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end
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end
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# Test if expression is prefix
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#
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# @param [Expression] other
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#
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# @return [Boolean]
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#
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# @api private
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#
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def prefix?(other)
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!match_length(other).zero?
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end
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# Register expression
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#
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# @return [undefined]
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#
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# @api private
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#
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def self.register(regexp)
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REGISTRY[regexp] = self
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end
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private_class_method :register
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# Parse input into expression or raise
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#
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# @param [String] syntax
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#
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# @return [Expression]
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# if expression is valid
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#
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# @raise [RuntimeError]
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# otherwise
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#
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# @api private
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#
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def self.parse(input)
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try_parse(input) or fail InvalidExpressionError, "Expression: #{input.inspect} is not valid"
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end
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# Parse input into expression
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#
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# @param [String] input
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#
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# @return [Expression]
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# if expression is valid
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#
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# @return [nil]
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# otherwise
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#
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# @api private
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#
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def self.try_parse(input)
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expressions = expressions(input)
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case expressions.length
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when 0
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when 1
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expressions.first
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else
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fail AmbigousExpressionError, "Ambigous expression: #{input.inspect}"
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end
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end
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# Return expressions for input
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#
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# @param [String] input
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#
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# @return [Classifier]
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# if classifier can be found
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#
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# @return [nil]
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# otherwise
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#
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# @api private
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#
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def self.expressions(input)
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REGISTRY.each_with_object([]) do |(regexp, klass), expressions|
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match = regexp.match(input)
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next unless match
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expressions << klass.new(match)
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end
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end
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private_class_method :expressions
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end # Expression
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end # Mutant
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