lib/zenlish/parser/zparser.rb in zenlish-0.1.15 vs lib/zenlish/parser/zparser.rb in zenlish-0.1.16

@@ -2,29 +2,58 @@
 
 require_relative '../lang/zenlish_grammar'
 
 module Zenlish
   class ZParser
+    # @!attribute [r] engine
+    #   @return [Rley::Engine] Facade object of Rley library
     attr_reader(:engine)
 
     def initialize
       # Create a Rley facade object
-      @engine = Rley::Engine.new
+      @engine = Rley::Engine.new do |config|
+        config.diagnose = true
+      end
 
       # Step 1. Load Zenlish grammar
       @engine.use_grammar(ZenlishGrammar)
     end
 
+    # Parse the sequence of words into a parse tree.
+    # @raise [StandardError] Fails when the parse is ambiguous.
+    # @return [Rley::PTree;;ParseTree] the resulting parse tree.
     def parse(tokenSeq)
+      result = earley_parse(tokenSeq)
+
+      # Convert into a parse tree
+      engine.to_ptree(result)
+    end
+
+    alias to_ptree parse
+
+    # Parse the sequence of words into a parse forest.
+    # Parse forests are needed when dealing with ambiguous input.
+    # @return [Rley::SPPF::ParseForest] the resulting parse forest.
+    def to_pforest(tokenSeq)
+      result = earley_parse(tokenSeq)
+      # puts result
+
+      # Convert into a parse forest
+      engine.to_pforest(result)
+    end
+
+    private
+
+    def earley_parse(tokenSeq)
       result = engine.parse(tokenSeq)
 
       unless result.success?
         # Stop if the parse failed...
         line1 = "Parsing failed\n"
         line2 = "Reason: #{result.failure_reason.message}"
         raise StandardError, line1 + line2
       end
 
-      return engine.to_ptree(result)
+      result
     end
   end # class
 end # module