rust-clippy/clippy_lints/src/utils/comparisons.rs
2016-05-27 13:03:58 +02:00

23 lines
686 B
Rust

use rustc::hir::{BinOp_, Expr};
#[derive(PartialEq, Eq, Debug, Copy, Clone)]
pub enum Rel {
Lt,
Le,
Eq,
Ne,
}
/// Put the expression in the form `lhs < rhs` or `lhs <= rhs`.
pub fn normalize_comparison<'a>(op: BinOp_, lhs: &'a Expr, rhs: &'a Expr)
-> Option<(Rel, &'a Expr, &'a Expr)> {
match op {
BinOp_::BiLt => Some((Rel::Lt, lhs, rhs)),
BinOp_::BiLe => Some((Rel::Le, lhs, rhs)),
BinOp_::BiGt => Some((Rel::Lt, rhs, lhs)),
BinOp_::BiGe => Some((Rel::Le, rhs, lhs)),
BinOp_::BiEq => Some((Rel::Eq, rhs, lhs)),
BinOp_::BiNe => Some((Rel::Ne, rhs, lhs)),
_ => None,
}
}