update tests
refactored for code generation
removed deprecation from ToReturnNode()
adding assert to grammar
Merge branch 'master' of github.com:konoha-project/libzen
testing extended type checker
update test cases
bug fixed: string token needs to contain double quote
Merge branch 'master' of github.com:konoha-project/libzen
adding DeSugar to ZNode
adding assert
just refactoring
refactored in ast