aikozhaoz/core-parser

Core-Parser

How to run

• cd to the Core-Parser folder
• To compile, run javac Main.java in your terminal
• To run the actual program, run javac Main.java testfile

Project Description

• A parser for a version of the Core language, a pretend language. The parser parses through the whole program and check if there is any syntax/semantic error.

Scanner Class

• Scanner:
  • The class constructor takes as input the name of the input file and finds the first token (the current token)
• tokenize:
  • This method should return a tokens list.
• currentToken:
  • This method should return the token the scanner is currently on, without consuming that token.
• nextToken:
  • This method should advance the scanner to the next token in the stream (the next token becomes the current token).
• getID:
  • If the current token is ID, then this method should return the string value of the identifier.
• getCONST:
  • If the current token is CONST, then this method should return the value of the constant.
• expectedToken:
  • Return if the current token == given Core c. If so, dequeues the tokens.

Utility class

• expectedhelper:
  • If the current token is an invalid token, print out error message
  • If the current token is not expected token print out error message, expected token and curren token.
• errorhelper:
  • If the current token is an invalid token, print out error message
  • If the current token is not expected token print out error message, expected tokens and curren token.
• DoubleDeclarationError:
  • Print out error message to notify user the file has double declared variable.
• UseUndeclaredIdError:
  • Print out error message to notify user the file used undeclared variable.
• DeclaredTypeError:
  • Print out error message to notify user the file contains wrongly declared variable.