Add bin and edit workflow

bin/gems/liquid-4.0.4/lib/liquid/parser.rb

@@ -0,0 +1,90 @@
+module Liquid
+  class Parser
+    def initialize(input)
+      l = Lexer.new(input)
+      @tokens = l.tokenize
+      @p = 0 # pointer to current location
+    end
+
+    def jump(point)
+      @p = point
+    end
+
+    def consume(type = nil)
+      token = @tokens[@p]
+      if type && token[0] != type
+        raise SyntaxError, "Expected #{type} but found #{@tokens[@p].first}"
+      end
+      @p += 1
+      token[1]
+    end
+
+    # Only consumes the token if it matches the type
+    # Returns the token's contents if it was consumed
+    # or false otherwise.
+    def consume?(type)
+      token = @tokens[@p]
+      return false unless token && token[0] == type
+      @p += 1
+      token[1]
+    end
+
+    # Like consume? Except for an :id token of a certain name
+    def id?(str)
+      token = @tokens[@p]
+      return false unless token && token[0] == :id
+      return false unless token[1] == str
+      @p += 1
+      token[1]
+    end
+
+    def look(type, ahead = 0)
+      tok = @tokens[@p + ahead]
+      return false unless tok
+      tok[0] == type
+    end
+
+    def expression
+      token = @tokens[@p]
+      if token[0] == :id
+        variable_signature
+      elsif [:string, :number].include? token[0]
+        consume
+      elsif token.first == :open_round
+        consume
+        first = expression
+        consume(:dotdot)
+        last = expression
+        consume(:close_round)
+        "(#{first}..#{last})"
+      else
+        raise SyntaxError, "#{token} is not a valid expression"
+      end
+    end
+
+    def argument
+      str = ""
+      # might be a keyword argument (identifier: expression)
+      if look(:id) && look(:colon, 1)
+        str << consume << consume << ' '.freeze
+      end
+
+      str << expression
+      str
+    end
+
+    def variable_signature
+      str = consume(:id)
+      while look(:open_square)
+        str << consume
+        str << expression
+        str << consume(:close_square)
+      end
+      if look(:dot)
+        str << consume
+        str << variable_signature
+      end
+      str
+    end
+  end
+end