daisy/src/evaluate.rs

62 lines
1.0 KiB
Rust

use crate::tokens::Token;
#[inline(always)]
fn get_at_coords<'a>(g: &'a mut Token, coords: &Vec<usize>) -> &'a mut Token {
let mut h = &mut *g;
for t in coords.iter() {
let inner = h.get_args().unwrap();
h = &mut inner[*t];
}
return h;
}
pub fn evaluate(
mut g: Token,
) -> Result<Token, ()> {
let mut coords: Vec<usize> = Vec::with_capacity(16);
coords.push(0);
'outer: loop {
let mut h = &mut g;
for t in coords.iter() {
let inner = h.get_args();
if inner.is_none() || *t >= inner.as_ref().unwrap().len() {
coords.pop();
let p = get_at_coords(&mut g, &coords);
let e = p.eval();
*p = e;
if coords.len() == 0 { break 'outer; }
let l = coords.pop().unwrap();
coords.push(l + 1);
continue 'outer;
}
h = &mut inner.unwrap()[*t];
}
match h {
Token::Operator(_,_,_)
=> {
coords.push(0);
continue 'outer;
},
Token::Constant(_,_,_) |
Token::Number(_,_) => {
let l = coords.pop().unwrap();
coords.push(l + 1);
continue 'outer;
}
};
}
return Ok(g);
}