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Commit 7d6d08c6 authored by Per's avatar Per
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precedence wip iterative

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with 75 additions and 118 deletions
examples/main2.rs
+ 75
− 118
View file @ 7d6d08c6
......@@ -26,6 +26,18 @@ pub enum Expr {
BinOp(Box<Expr>, Op, Box<Expr>),
}
// // deep cloning (is it necessary)
// impl Clone for Expr {
// fn clone(&self) -> Expr {
// match self {
// Expr::BinOp(l, op, r) => Expr::BinOp (
// l.clone(), *op, r.clone()
// ),
// Expr::Num(i) => Expr::Num(*i)
// }
// }
// }
pub fn parse_i32(i: &str) -> IResult<&str, Expr> {
map(digit1, |digit_str: &str| {
Expr::Num(digit_str.parse::<i32>().unwrap())
......@@ -58,7 +70,9 @@ fn parse_expr(i: &str) -> IResult<&str, Expr> {
fn math_expr(e: &Expr) -> String {
match e {
Expr::Num(i) => format!("{}", i),
Expr::BinOp(l, op, r) => format!("({} {:?} {})", math_expr(l), op, math_expr(r)),
Expr::BinOp(l, op, r) => {
format!("({:?}, {}, {})", op, math_expr(l), math_expr(r))
}
}
}
......@@ -94,148 +108,91 @@ fn climb_op(op: &Op) -> (u8, Ass) {
}
}
fn climb(e: Expr) -> Expr {
println!("climb {:?}", &e);
// fn build_expr(l:&Expr, op:&Op, r:&Expr) -> Expr {
// Expr::BinOp(Box::new(*l), *op, Box::new(*r))
// }
fn climb(e: Expr, min_prec: u8) -> Expr {
println!("in climb {}, {}", math_expr(&e), min_prec);
match e.clone() {
Expr::Num(_) => e,
Expr::BinOp(l, op, r) => {
let (prec, ass) = climb_op(&op);
let new_r = *r;
match new_r.clone() {
Expr::Num(_) => e,
Expr::BinOp(r_l, r_op, r_r) => {
let (r_prec, r_ass) = climb_op(&r_op);
if r_prec
< prec
+ match ass {
Ass::Left => 1,
Ass::Right => 0,
}
{
// push upwards
println!("push upwards {:?} {:?}", op, r_op);
let new_l = Expr::BinOp(Box::new(*l), op, Box::new(*r_l));
let new_top = Expr::BinOp(Box::new(new_l), r_op, Box::new(climb(*r_r)));
new_top
} else {
Expr::BinOp(l, op, Box::new(climb(new_r)))
}
}
let mut res = e.clone();
let mut cur = e.clone();
while let Expr::BinOp(l, op, r) = cur {
cur = *r.clone();
let rhs = climb(
cur.clone(),
prec + match ass {
Ass::Left => 1,
Ass::Right => 0,
},
);
println!("rhs {}", math_expr(&rhs));
res = Expr::BinOp(Box::new(res), op, Box::new(rhs))
}
res
}
}
}
fn test_eq(s: &str, v: i32) {
assert_eq!(math_eval(&climb(parse_expr(s).unwrap().1)), v);
}
// fn test_eq(s: &str, v: i32) {
// assert_eq!(math_eval(&climb(parse_expr(s).unwrap().1), 0), v);
// }
#[test]
fn climb1() {
test_eq("1-2+3", 1 - 2 + 3);
}
// #[test]
// fn climb1() {
// test_eq("1-2+3", 1 - 2 + 3);
// }
#[test]
fn climb2() {
test_eq("1*2+3", 1 * 2 + 3);
}
// #[test]
// fn climb2() {
// test_eq("1*2+3", 1 * 2 + 3);
// }
#[test]
fn climb3() {
test_eq("1*2+3*4-5", 1 * 2 + 3 * 4 - 5);
}
// #[test]
// fn climb3() {
// test_eq("1*2+3*4-5", 1 * 2 + 3 * 4 - 5);
// }
#[test]
fn climb4() {
test_eq("2^5", 2i32.pow(5));
}
// #[test]
// fn climb4() {
// test_eq("2^5", 2i32.pow(5));
// }
#[test]
fn climb5() {
test_eq("2*3+4+5", 2 * 3 + 4 + 5);
}
// #[test]
// fn climb5() {
// test_eq("2*3+4+5", 2 * 3 + 4 + 5);
// }
#[test]
fn climb6() {
test_eq("2*3-4*5-2", 2 * 3 - 4 * 5 - 2);
}
// #[test]
// fn climb6() {
// test_eq("2*3-4*5-2", 2 * 3 - 4 * 5 - 2);
// }
#[test]
fn climb_err() {
test_eq("2 + 2 ^ 5 -3", 2 + 2i32.pow(5 - 3));
}
// #[test]
// fn climb_err() {
// test_eq("2 + 2 ^ 5 -3", 2 + 2i32.pow(5 - 3));
// }
fn climb_test(s: &str, v: i32) {
let p = parse_expr(s).unwrap().1;
println!("{:?}", &p);
println!("math {}", math_expr(&p));
let r = climb(p);
let r = climb(p, 0);
println!("r {:?}", &r);
println!("math r {}", math_expr(&r));
println!("eval r {} = {} ", math_eval(&r), v);
}
fn main() {
climb_test("2*5+10+10", 2*5+10+10);
climb_test("2*5+10*11-1", 2*5+10*11-1);
climb_test("2*5+10*11-2+12", 2*5+10*11-1+12);
// println!();
// let p = parse_expr("3+2*5+27").unwrap().1;
// println!("{:?}", &p);
// println!("math {}", math_expr(&p));
// let r = climb(p);
// println!("r {:?}", &r);
// println!("math r {}", math_expr(&r));
// println!("eval r {} = {} ", math_eval(&r), 3 + 2 * 5 + 27);
// println!();
// let p = parse_expr("2*5+11*27+13").unwrap().1;
// println!("{:?}", &p);
// println!("math {}", math_expr(&p));
// let r = climb(p);
// println!("r {:?}", &r);
// println!("math r {}", math_expr(&r));
// println!("eval r {} = {} ", math_eval(&r), 2 * 5 + 11 * 27 + 13);
// println!();
// let p = parse_expr("1-2-3").unwrap().1;
// println!("{:?}", &p);
// println!("math {}", math_expr(&p));
// let r = climb(p);
// println!("r {:?}", &r);
// println!("math r {}", math_expr(&r));
// println!("eval r {} = {} ", math_eval(&r), 1 - 2 - 3);
// let i = "1-2-3-4";
// println!("\n{}", i);
// let p = parse_expr(i).unwrap().1;
// println!("{:?}", &p);
// println!("math {}", math_expr(&p));
// println!("eval r {} = {} ", math_eval(&p), 1 - 2 - 3 - 4);
// let r = climb(p);
// println!("r {:?}", &r);
// println!("math r {}", math_expr(&r));
// println!("eval r {} = {} ", math_eval(&r), ((1 - 2) - 3) - 4);
// let i = "2*3-4*5-2";
// println!("\n{}", i);
// let p = parse_expr(i).unwrap().1;
// println!("{:?}", &p);
// println!("math {}", math_expr(&p));
// println!("eval r {} = {} ", math_eval(&p), 2 * 3 - 4 * 5 - 2);
// let r = climb(p);
// println!("r {:?}", &r);
// println!("math r {}", math_expr(&r));
// println!("eval r {} = {} ", math_eval(&r), (2 * 3) - (4 * 5) - 2);
// let i = "2^5-1";
// println!("\n{}", i);
// let p = parse_expr(i).unwrap().1;
// println!("{:?}", &p);
// println!("math {}", math_expr(&p));
// println!("eval r {} = {} ", math_eval(&p), 1 - 2 - 3 - 4);
// let r = climb(p);
// println!("r {:?}", &r);
// println!("math r {}", math_expr(&r));
// println!("eval r {} = {} ", math_eval(&r), ((1 - 2) - 3) - 4);
// climb_test("2*5+10+10", 2*5+10+10);
// climb_test("2*5+10*11-1", 2*5+10*11-1);
// climb_test("2*5+10*11-2+12", 2*5+10*11-1+12);
// climb_test("1+2*3-4+5", 1 + 2 * 3 - 4 + 5);
climb_test("1", 1);
climb_test("1+2", 1 + 2);
}
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