Hello,

Im developing a small python like language using flex, byacc (for lexical and parsing) and C++, but i have a few questions regarding scope control.

just as python it uses white spaces (or tabs) for identation, not only that but i want to implement index breaking like for instance if you type "break 2" inside a while loop thats inside another while loop it would not only break from the last one but from the first loop as well (hence the number 2 after break) and so on.

example:

while 1
    while 1
        break 2
    end
end
#after break 2 it would jump right here

but since i dont have an "anti" tab character to check when a scope ends (like C for example i would just use the '}' char) i was wondering if this method would the the best:

i would define a global variable, like "int tabIndex" on my yacc file that i would access in my lex file using extern. then everytime i find a tab character on my lex file i would increment that variable by 1. when parsing on my yacc file if i find a "break" keyword i would decrement by the amount typed after it from the tabIndex variable, and when i reach and EOF after compiling and i get a tabIndex != 0 i would output compilation error.

now the problem is, whats the best way to see if the identation got reduced, should i read \b (backspace) chars from lex and then reduce the tabIndex variable (when the user doesnt use break)?

another method to achieve this?

also just another small question, i want every executable to have its starting point on the function called start() should i hardcode this onto my yacc file?

sorry for the long question any help is greatly appretiated. also if someone can provide an yacc file for python would be nice as a guideline (tried looking on google and had no luck).

thanks in advance.