lib/parser/koi-reference-parser.treetop in koi-reference-parser-0.0.2 vs lib/parser/koi-reference-parser.treetop in koi-reference-parser-0.0.3

@@ -1,15 +1,27 @@
+# This file is a Parsing Expression Grammar (PEG) for the Koi
+# programming language. It is interpreted by the PEG engine Treetop.
+
+# More info on PEGs: http://en.wikipedia.org/wiki/Parsing_expression_grammar
+# More info on Treetop: http://treetop.rubyforge.org/
+
 grammar KoiReferenceParser
 
+  ##################
+  # Program structure
+
   rule block
     statement+ <Block>
   end
 
   rule statement
     space? ( hash_assignment / assignment / if / unless / function_call ) ';'? space? <Statement>
   end
   
+  ##################
+  # Literals
+  
   rule nil
     "nil" <NilLiteral>
   end
   
   rule true
@@ -34,10 +46,28 @@
   
   rule identifier
     '$'? [a-zA-Z] [a-zA-Z0-9_]* <Identifier>
   end
   
+  ##################
+  # Hash literals
+  
+  rule hash
+    '{' key_value_list? '}' <HashLiteral>
+  end
+  
+  rule key_value_list
+    key_value+ <KeyValueList>
+  end
+  
+  rule key_value
+    space? expression space? '=>' space? expression space? ','? <KeyValue>
+  end
+  
+  ##################
+  # Assignment
+  
   rule hash_assignment
     identifier hash_accessor_list space? assignment_operator space? ( hash / function_definition / expression ) <HashAssignment>
   end
   
   rule assignment
@@ -68,94 +98,70 @@
   
   rule function_definition
     'function(' space? identifier space? ')' 
       block
     space? 'end' <FunctionDefinition>
-  end
-  
+  end  
+
   ##################
-  # Whitespace
+  # Hash component access
   
-  rule space
-    [\s]+ <Whitespace>
+  rule hash_access
+    identifier hash_accessor_list <HashAccess>
   end
   
-  ##################
-  # Hashes
-  
   rule hash_accessor_list
     hash_accessor+ <HashAccessorList>
   end
   
   rule hash_accessor
     '[' expression ']' <HashAccessor>
   end
-  
-  rule hash
-    '{' key_value_list? '}' <HashLiteral>
-  end
-  
-  rule key_value_list
-    key_value+ <KeyValueList>
-  end
-  
-  rule key_value
-    space? expression space? '=>' space? expression space? ','? <KeyValue>
-  end
-  
-  rule key
-    space? expression space? <Key>
-  end
-  
-  rule value
-    space? expression space? <Value>
-  end
 
   ##################
   # Expressions
   
   rule expression
     space? (hash_access / comparative / additive) <Expression>
   end
   
-  rule hash_access
-    identifier hash_accessor_list <HashAccess>
-  end
-  
   rule comparative
-    additive space? (equality_operator / inequality_operator / greater_than_operator / less_than_operator) space? additive <ComparativeExpression>
+    additive space? comparative_operator space? additive <ComparativeExpression>
   end
   
   rule additive
     multitive space? additive_operator space? additive <AdditiveExpression>
     /
     multitive 
   end
-  
-  rule additive_operator
-    addition_operator 
-    /
-    subtraction_operator 
-  end
 
   rule multitive
     primary space? multitive_operator space? multitive <MultitiveExpression>
     /
     primary 
   end
   
-  rule multitive_operator
-    multiplication_operator 
-    /
-    division_operator  
-  end  
-  
   rule primary
     function_call / nil / false / true / identifier / float / integer / string 
     /
     '(' space? expression space? ')' <Expression>
   end
+  
+  ##################
+  # Operator sets
+  
+  rule comparative_operator
+    equality_operator / inequality_operator / greater_than_operator / less_than_operator
+  end
+  
+  rule additive_operator
+    addition_operator / subtraction_operator 
+  end
+  
+  rule multitive_operator
+    multiplication_operator / division_operator  
+  end
 
   ##################
   # Operators
 
   rule assignment_operator
@@ -190,8 +196,15 @@
     '>' <GreaterThanOperator>
   end
   
   rule less_than_operator
     '<' <LessThanOperator>
+  end
+  
+  ##################
+  # Whitespace
+  
+  rule space
+    [\s]+
   end
 
 end