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C--, like C but a bit worse

This project is a compiler for a toy language called c--, as the name suggests it is similar to C but a bit simplified. My plan is to iteratively add new features, but is very unlike that it ever goes from c-- to full c89 (or newer).

Note: This is strictly a hobby project and is not built to be used for production purposes

Formal Grammar specification

The language grammar expressed in EBNF:

// Functions
function -> prototype expr
prototype -> int identifier '(' (int identifier)* ')'
extern -> 'extern' prototype

// Expressions
expr -> primary_expr bin_expr
primary_expr -> identifier_expr | number_expr | parenthesis_expr 
number_expr -> NUMBER
parenthesis_expr -> '(' expr ')'
identifier_expr ->  identifier // variable
                    | identifier '(' expr* ')' // func call with comma separated arguments

// Binary expressions
bin_expr -> (bin_op primary_expr)* // left recursive
bin_op -> '+' | '-' | '*' | '<'

Implementation details

Lexer

...

Parser

Handwritten recursive decent parser

Backend

Is currently planned to be written in llvm.

TODO list:

  • Working compiler :-)
  • Up-to-date readme
  • Re-introduce handwritten parser and lexer