parser.rb in sexpistol-0.1.2

- old
+ new

@@ -8,23 +8,25 @@
     STRING =      /"([^"\\]|\\.)*"/.freeze
     FLOAT =       /[\-+]? [0-9]+ ((e[0-9]+) | (\.[0-9]+(e[0-9]+)?)) (?=[\s()])/x.freeze
     INTEGER =     /([\-+]?[0-9]+)(?=[\s()])/.freeze
     SYMBOL =      /[^0-9()\s]+[^()\s]*/.freeze
 
-    def initialize(string)
+    def initialize(string, parse_ruby_keyword_literals = false)
       raise 'String given is not an s-expression' if string.strip[0] != '('
       raise 'Invalid s-expression' if string.count('(') != string.count(')')
 
+      @parse_ruby_keyword_literals = parse_ruby_keyword_literals
+
       super(string.strip)
     end
 
     def parse(level = 0, exp = [])
       until eos?
         case token = fetch_token
         when ')' then break
         when '(' then exp << parse(level + 1)
-        when String, Integer, Float, Symbol then exp << token
+        when String, Integer, Float, Symbol then exp << convert_ruby_keyword_literals(token)
         end
       end
 
       if level.zero?
         exp = exp.first if exp.first.is_a?(Array) && exp.length == 1
@@ -42,8 +44,19 @@
       return matched.to_f   if scan(FLOAT)
       return matched.to_i   if scan(INTEGER)
       return matched.to_sym if scan(SYMBOL)
 
       raise "Invalid token at position #{pos} near '#{scan(/.{0,20}/)}'."
+    end
+
+    def convert_ruby_keyword_literals(token)
+      return token unless @parse_ruby_keyword_literals && token.is_a?(Symbol)
+
+      case token
+      when :nil then nil
+      when :true then true
+      when :false then false
+      else token
+      end
     end
   end
 end