Generate yacc prototype
Pend interpreter test and make test green
Accept integer and null
Refactor parser about NUMBER
Support single quote
Parse boolean object
Support IDENTIFIER
Fix parser test
Enable parsing simple application
Write deep parser tests
Enable string parsing
Remove pending from test interpreter
Enable parsing multiple expressions
Fix nits
Absolutely disable single quote parsing
Enable parsing S expression
Merge pull request #1 from k0kubun/yacc

Rewrite parser by yacc