C compiler

this is a C compiler with rust implementation.

• [√] Lexer
• [√] Parser
• [√] Evaluator(which interpreted the AST like script language, helps to check the grammar correctness when the IR generator unfinished.)
• [] IR Generator
• [] Machine code Generator

current support features:

• simple calculation (add, subtract, multipy, devide)
• var declaration(simple declaration or declaration with init)
• var assignment

next things want to do:

• array support (like C) (without initilization first)
• condition control

go!!!!!