dontbelieveme / stack Goto Github PK

Now that the error refactoring is complete, I think refactoring other parts of the code base should be done as well. Rename functions that are confusing to understand, refactoring the parser, and cleaning up the code in general. Adding better documentation is in order also.

I have one question about the Macro struct in parse.h. What does it do?

Currently error reporting is abysmal and needs some serious refactoring. Certain functions can't report an error if something went awry because: a) the return value is void or b) the function does return a value but you can't return error codes because it would limit the abilities of particular operations.

Take stack_pop() for example. It pops the top item off the stack and returns it. If you pop from an empty stack that is called a stack underflow. If the function returns any number like -1 to signify a stack underflow, then arithmetic operations with that designated error number is impossible.

Another example is stack_dup(). Its implementation pops off a value then pushes it twice back onto the stack. What if the stack is empty? Like said before, popping from an empty stack yields a stack underflow. How do we let the calling user of stack_dup() know that an error happened? We can't currently because of how the function is setup.

My proposal for the solution is to allow all functions that return a pointer return 0 on failure and every other function have an additional output parameter for the error code. Another one is all functions return a status code and the return value is an output parameter.

For example:

stack *stack_new()

becomes

error_code_t stack_new(stack **new_stack);

I wanted to run this by you before doing the refactoring to see what you think.

When I began this project I had no idea about parsers or anything. Now I return, armed with the knowledge of several crudely implemented simple parsers. Aha!