Split Token class into Token/Pattern

lib/propane/pattern.rb

@@ -0,0 +1,53 @@
+class Propane
+
+  class Pattern
+
+    # @return [String, nil]
+    #   Pattern.
+    attr_reader :pattern
+
+    # @return [Token, nil]
+    #   Token to be returned by this pattern.
+    attr_reader :token
+
+    # @return [Integer, nil]
+    #   Line number where the pattern was defined in the input grammar.
+    attr_reader :line_number
+
+    # @return [Regex::NFA, nil]
+    #   Regex NFA for matching the pattern.
+    attr_reader :nfa
+
+    # Construct a Pattern.
+    #
+    # @param options [Hash]
+    #   Optional parameters.
+    # @option options [Boolean] :drop
+    #   Whether this is a drop pattern.
+    # @option options [String, nil] :pattern
+    #   Pattern.
+    # @option options [Token, nil] :token
+    #   Token to be returned by this pattern.
+    # @option options [Integer, nil] :line_number
+    #   Line number where the token was defined in the input grammar.
+    def initialize(options)
+      @drop = options[:drop]
+      @pattern = options[:pattern]
+      @token = options[:token]
+      @line_number = options[:line_number]
+      regex = Regex.new(@pattern)
+      regex.nfa.end_state.accepts = self
+      @nfa = regex.nfa
+    end
+
+    # Whether the pattern is a drop pattern.
+    #
+    # @return [Boolean]
+    #   Whether the pattern is a drop pattern.
+    def drop?
+      @drop
+    end
+
+  end
+
+end