After writing a lexer, parser, compiler and virtual machine in C++ and ported parts to Python, Java and FreeBASIC - I think this is a good starting point. Most

After writing a lexer, parser, compiler and virtual machine in C++ and ported parts to Python, Java and FreeBASIC - I think this is a good starting point. Most of the concepts are pretty simple - it's when you get into if/while/for statements. Especially if you have nested if/while/for statements. Conceptually easy to implement using recursion but during the compilation phase keeping track of where you are at can be...difficult. I'll be the first to admit my implementation sucked but it worked.