lab: error: error handling
Merge branch 'master'
Merge branch 'master'
Parse try-catch statement
Add descriptions to some parsers
lab: error + cont + state
lab: add demo for cont-error and error-cont transformers stack
lab: add error-cont primitive evaliator
Add exceptions (try/catch/throw evaluating is not implemented yet)
Evaluate try/catch statement
Add string literals
Use values as exceptions (instead of using special Exception type)
Merge branch 'exceptions'