yu
An imperative toy programming language.
Usage
Requirements: GHC and Cabal.
The project can be compiled using cabal build. It can also be ran using cabal run.
Currently the program will lex & parse the source code, report potential errors and if no errors
were found it will print the AST.
$ cabal run yu -- ./examples/simple.yu
Examples
Note: Not fully functional, subject to change.
module main;
/*
* Add two integers, double result and return it.
*/
fun addTwice(x: int, y: int): int {
return (x + y) * 2;
}
/*
* Entry point of the program.
*/
fun main() {
let x: int = 5;
let y = 10;
let z = addTwice(x, y);
print(z); // -> 30
}
Grammar
module ::= (decl)*
decl ::= module_decl
| function_decl
module_decl ::= "module" IDENT ";"
function_decl ::= "fun" IDENT "(" param ("," param)* ")" "{" (statement ";")* "}"
param ::= IDENT ":" IDENT
statement ::= var_decl
| return
var_decl ::= "let" IDENT (":" IDENT) "=" expr
return ::= "return" expr
expr ::= expr_pre (call_tail)* (op_tail)*
expr_pre ::= literal
| IDENT
| "(" expr ")"
call_tail ::= "(" expr ("," expr)* ")"
literal ::= INT_LITERAL
op_tail ::= operator expr
OP_IDENT ::= _one or more punctuation characters_
INT_LITERAL ::= _one or more decimal digits_
IDENT ::= _one or more alphanumeric characters or underscore_
License
Licensed under the MIT License.