Compiler error handling

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Compiler error handling

For fun I made my compiler a bit more robust by looking for common Jack language errors.  Here is list of what I've implemented:

-[syntax errors are already caught by the tokenizer/parser, as part of the project.
For example, "var boolean int;" is a syntax error because int is a keyword, and should be an identifier]

-unexpected token after end of class

-class name and file name mismatch

-duplicate variables within the same scope

-undeclared variables

-duplicate subroutine declaration within the same class

-subroutine not found (if called in a way where it’s expected to be in this class)

-calling a method from within a function, where 'this' is implied

-accessing a field from within a function

-accessing 'this' from within a function

-subroutine call/declaration mismatch (in terms of kind: e.g. called as a method but declared as a function)

-subroutine call/declaration mismatch (in terms of nArgs: e.g, called with 1 arg but declared with 2 args)

-subroutine has no return statement

-return type of a constructor is not of the class type

-a constructor that does not return 'this'

-a non-void subroutine that returns no expression

-a void subroutine that returns an expression

-integer constant exceeds 32767

Most of these were trivial to implement.  The errors with regard to subroutine calls matching their declarations -that was more work, but not too bad. Of course, in that case, I only worry about calls that are made to subroutines within the class. I don't check external calls.

I'm sure there are many more errors I could implement. Would love to hear your ideas.
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Re: Compiler error handling

Nice. One type of error common error is to miss a semicolon or a closing curly brace, bracket or parenthesis. This kind of error is harder to pinpoint. The parser normally detects and reports the error a few lines later, which is confusing, especially for less experienced programmers.

I don't know how easy or how hard it would be to do such analysis, but it might be an interesting exercise.