added some constants to parser
added another constant
added pl0 keywords
added all constant now write lexycal analyzer
added some rules
added condition and ident all code
added some auxiliar rules to block
fixed a litle bug
grammar done
fixed some errors
Merge pull request #2 from Academic-KevinRobayna/feature-parser

Feature parser
Merge pull request #3 from Academic-KevinRobayna/development

Development