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|
use hir::db::HirDatabase;
use ra_syntax::ast::{AstNode, BinExpr, BinOp};
use crate::{Assist, AssistCtx, AssistId};
// Assist: flip_binexpr
//
// Flips operands of a binary expression.
//
// ```
// fn main() {
// let _ = 90 +<|> 2;
// }
// ```
// ->
// ```
// fn main() {
// let _ = 2 + 90;
// }
// ```
pub(crate) fn flip_binexpr(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
let expr = ctx.find_node_at_offset::<BinExpr>()?;
let lhs = expr.lhs()?.syntax().clone();
let rhs = expr.rhs()?.syntax().clone();
let op_range = expr.op_token()?.text_range();
// The assist should be applied only if the cursor is on the operator
let cursor_in_range = ctx.frange.range.is_subrange(&op_range);
if !cursor_in_range {
return None;
}
let action: FlipAction = expr.op_kind()?.into();
// The assist should not be applied for certain operators
if let FlipAction::DontFlip = action {
return None;
}
ctx.add_action(AssistId("flip_binexpr"), "flip binary expression", |edit| {
edit.target(op_range);
if let FlipAction::FlipAndReplaceOp(new_op) = action {
edit.replace(op_range, new_op);
}
edit.replace(lhs.text_range(), rhs.text());
edit.replace(rhs.text_range(), lhs.text());
});
ctx.build()
}
enum FlipAction {
// Flip the expression
Flip,
// Flip the expression and replace the operator with this string
FlipAndReplaceOp(&'static str),
// Do not flip the expression
DontFlip,
}
impl From<BinOp> for FlipAction {
fn from(op_kind: BinOp) -> Self {
match op_kind {
BinOp::Assignment => FlipAction::DontFlip,
BinOp::AddAssign => FlipAction::DontFlip,
BinOp::DivAssign => FlipAction::DontFlip,
BinOp::MulAssign => FlipAction::DontFlip,
BinOp::RemAssign => FlipAction::DontFlip,
BinOp::ShrAssign => FlipAction::DontFlip,
BinOp::ShlAssign => FlipAction::DontFlip,
BinOp::SubAssign => FlipAction::DontFlip,
BinOp::BitOrAssign => FlipAction::DontFlip,
BinOp::BitAndAssign => FlipAction::DontFlip,
BinOp::BitXorAssign => FlipAction::DontFlip,
BinOp::GreaterTest => FlipAction::FlipAndReplaceOp("<"),
BinOp::GreaterEqualTest => FlipAction::FlipAndReplaceOp("<="),
BinOp::LesserTest => FlipAction::FlipAndReplaceOp(">"),
BinOp::LesserEqualTest => FlipAction::FlipAndReplaceOp(">="),
_ => FlipAction::Flip,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::helpers::{check_assist, check_assist_not_applicable, check_assist_target};
#[test]
fn flip_binexpr_target_is_the_op() {
check_assist_target(flip_binexpr, "fn f() { let res = 1 ==<|> 2; }", "==")
}
#[test]
fn flip_binexpr_not_applicable_for_assignment() {
check_assist_not_applicable(flip_binexpr, "fn f() { let mut _x = 1; _x +=<|> 2 }")
}
#[test]
fn flip_binexpr_works_for_eq() {
check_assist(
flip_binexpr,
"fn f() { let res = 1 ==<|> 2; }",
"fn f() { let res = 2 ==<|> 1; }",
)
}
#[test]
fn flip_binexpr_works_for_gt() {
check_assist(
flip_binexpr,
"fn f() { let res = 1 ><|> 2; }",
"fn f() { let res = 2 <<|> 1; }",
)
}
#[test]
fn flip_binexpr_works_for_lteq() {
check_assist(
flip_binexpr,
"fn f() { let res = 1 <=<|> 2; }",
"fn f() { let res = 2 >=<|> 1; }",
)
}
#[test]
fn flip_binexpr_works_for_complex_expr() {
check_assist(
flip_binexpr,
"fn f() { let res = (1 + 1) ==<|> (2 + 2); }",
"fn f() { let res = (2 + 2) ==<|> (1 + 1); }",
)
}
#[test]
fn flip_binexpr_works_inside_match() {
check_assist(
flip_binexpr,
r#"
fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
match other.downcast_ref::<Self>() {
None => false,
Some(it) => it ==<|> self,
}
}
"#,
r#"
fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
match other.downcast_ref::<Self>() {
None => false,
Some(it) => self ==<|> it,
}
}
"#,
)
}
}
|
