Hi john I'm learning smacc as a challenge :) I read a review the tutorial that we extracted form your doc. I have the following expression FunctionTypeName = 'function' TypeNameList ( 'internal' | 'external' | 'constant' | 'payable' )* ( 'returns' TypeNameList )? and I started to handle the 'internal'.... Now my grammar does not succeed to parse (self parser parseFunctionTypeNameOptions: 'internal payable') Attempt one: did not work =================== FunctionTypeNameOptions : {{}} | FunctionTypeNameOptions "internal" 'option' {{}} | FunctionTypeNameOptions "external" 'option' {{}} | FunctionTypeNameOptions "constant" 'option' {{}} | FunctionTypeNameOptions "payable" 'option' {{}} Attempt two: did not work =================== FunctionTypeNameOptions : | FunctTypeNameOptions ; FunctTypeNameOptions : FunctTypeNameOptions "internal" 'option' {{}} | FunctTypeNameOptions "external" 'option' {{}} | FunctTypeNameOptions "constant" 'option' {{}} | FunctTypeNameOptions "payable" 'option' {{}} ; Attempt three: did not work ===================== FunctionTypeNameOptions : | FunctTypeNameOptions ; FunctTypeNameOptions : FunctTypeNameOption 'option' | FunctTypeNameOptions FunctTypeNameOption 'option' ; FunctTypeNameOption : "internal" 'option' {{}} | "external" 'option' {{}} | "constant" 'option' {{}} | "payable" 'option' {{}} ; I studied the JavaParser and I do not get why my version does not work modifiers_opt : | modifiers ; modifiers : modifier 'modifier' | modifiers modifier 'modifier' ; modifier : "public" 'token' {{Modifier}} | "protected" 'token' {{Modifier}} | "private" 'token' {{Modifier}} | "static" 'token' {{Modifier}} ; Thanks in advance. I could have try to do it in petitParser but I want to have a real experience with Smacc. Stef