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use std::ops::{Add, AddAssign}; use ::*; impl <T> Add<T> for Expr where T: Into<Expr> { type Output = Expr; fn add(self, rhs: T) -> Expr { Expr::Add(Box::new(self.clone()), Box::new(rhs.into())) } } impl <T> AddAssign<T> for Expr where T: Into<Expr> { fn add_assign(&mut self, rhs: T) { *self = self.clone() + rhs.into() } } impl Add<Expr> for f64 { type Output = Expr; fn add(self, rhs: Expr) -> Expr { Expr::Num(self) + rhs } } impl Add<Expr> for i64 { type Output = Expr; fn add(self, rhs: Expr) -> Expr { Expr::Num(self as f64) + rhs } } #[test] fn expr_f64() { let added = s!(x) + 3; assert_eq!(format!("{:?}", added), "Add(Symbol(\"x\"), Num(3.0))"); } #[test] fn f64_expr() { let added = 3 + s!(x); assert_eq!(format!("{:?}", added), "Add(Num(3.0), Symbol(\"x\"))"); } #[test] fn expr_expr() { let added = s!(x) + s!(y); assert_eq!(format!("{:?}", added), "Add(Symbol(\"x\"), Symbol(\"y\"))"); }