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use crate::eval::Num;
use num::BigInt;
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum UnOp {
Neg,
Sin,
Cos,
Tan,
Asin,
Acos,
Atan,
Sqrt,
Log,
Log10,
Log2,
Floor,
Ceil,
Round,
Abs,
}
impl UnOp {
fn eval(self, x: Num) -> Num {
use UnOp::*;
match self {
Neg => Num::Int(BigInt::from(0)).sub(x),
Sin => x.sin(),
Cos => x.cos(),
Tan => x.tan(),
Asin => x.asin(),
Acos => x.acos(),
Atan => x.atan(),
Sqrt => x.sqrt(),
Log => x.log(),
Log10 => x.log10(),
Log2 => x.log2(),
Floor => x.floor(),
Ceil => x.ceil(),
Round => x.round(),
Abs => x.abs(),
}
}
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum BinOp {
Pow,
Mul,
Div,
IntDiv,
Mod,
Add,
Sub,
}
impl BinOp {
fn eval(self, x: Num, y: Num) -> Num {
match self {
BinOp::Pow => x.pow(y),
BinOp::Mul => x.mul(&y),
BinOp::Div => x.div(y),
BinOp::IntDiv => x.int_div(y),
BinOp::Mod => x.modulo(y),
BinOp::Add => x.add(y),
BinOp::Sub => x.sub(y),
}
}
}
#[derive(Debug, PartialEq)]
pub enum Op {
Num(Num),
Un(UnOp),
Bin(BinOp),
}
pub fn eval(ops: impl Iterator<Item = Op>) -> Num {
let mut stack = Vec::new();
for op in ops {
match op {
Op::Num(n) => stack.push(n),
Op::Un(op) => {
let n = stack.pop().unwrap();
stack.push(op.eval(n));
}
Op::Bin(op) => {
let n2 = stack.pop().unwrap();
let n1 = stack.pop().unwrap();
stack.push(op.eval(n1, n2));
}
}
}
stack.pop().unwrap()
}
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