diff --git a/examples/main2.rs b/examples/main2.rs
index 7270d7a6e95c025aa76234d3e04a5291f68eb608..787cd45d4ac1a10d5340c6963d77362dc4b389f5 100644
--- a/examples/main2.rs
+++ b/examples/main2.rs
@@ -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);
}