135 lines
3.8 KiB
Rust
135 lines
3.8 KiB
Rust
use syntax::ast::{AstNode, BinExpr, BinOp};
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use crate::{AssistContext, AssistId, AssistKind, Assists};
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// Assist: flip_binexpr
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//
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// Flips operands of a binary expression.
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//
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// ```
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// fn main() {
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// let _ = 90 +$0 2;
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// }
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// ```
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// ->
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// ```
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// fn main() {
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// let _ = 2 + 90;
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// }
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// ```
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pub(crate) fn flip_binexpr(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
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let expr = ctx.find_node_at_offset::<BinExpr>()?;
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let lhs = expr.lhs()?.syntax().clone();
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let rhs = expr.rhs()?.syntax().clone();
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let op_range = expr.op_token()?.text_range();
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// The assist should be applied only if the cursor is on the operator
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let cursor_in_range = op_range.contains_range(ctx.frange.range);
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if !cursor_in_range {
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return None;
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}
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let action: FlipAction = expr.op_kind()?.into();
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// The assist should not be applied for certain operators
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if let FlipAction::DontFlip = action {
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return None;
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}
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acc.add(
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AssistId("flip_binexpr", AssistKind::RefactorRewrite),
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"Flip binary expression",
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op_range,
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|edit| {
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if let FlipAction::FlipAndReplaceOp(new_op) = action {
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edit.replace(op_range, new_op);
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}
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edit.replace(lhs.text_range(), rhs.text());
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edit.replace(rhs.text_range(), lhs.text());
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},
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)
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}
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enum FlipAction {
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// Flip the expression
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Flip,
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// Flip the expression and replace the operator with this string
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FlipAndReplaceOp(&'static str),
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// Do not flip the expression
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DontFlip,
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}
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impl From<BinOp> for FlipAction {
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fn from(op_kind: BinOp) -> Self {
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match op_kind {
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kind if kind.is_assignment() => FlipAction::DontFlip,
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BinOp::GreaterTest => FlipAction::FlipAndReplaceOp("<"),
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BinOp::GreaterEqualTest => FlipAction::FlipAndReplaceOp("<="),
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BinOp::LesserTest => FlipAction::FlipAndReplaceOp(">"),
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BinOp::LesserEqualTest => FlipAction::FlipAndReplaceOp(">="),
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_ => FlipAction::Flip,
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
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#[test]
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fn flip_binexpr_target_is_the_op() {
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check_assist_target(flip_binexpr, "fn f() { let res = 1 ==$0 2; }", "==")
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}
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#[test]
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fn flip_binexpr_not_applicable_for_assignment() {
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check_assist_not_applicable(flip_binexpr, "fn f() { let mut _x = 1; _x +=$0 2 }")
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}
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#[test]
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fn flip_binexpr_works_for_eq() {
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check_assist(flip_binexpr, "fn f() { let res = 1 ==$0 2; }", "fn f() { let res = 2 == 1; }")
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}
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#[test]
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fn flip_binexpr_works_for_gt() {
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check_assist(flip_binexpr, "fn f() { let res = 1 >$0 2; }", "fn f() { let res = 2 < 1; }")
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}
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#[test]
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fn flip_binexpr_works_for_lteq() {
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check_assist(flip_binexpr, "fn f() { let res = 1 <=$0 2; }", "fn f() { let res = 2 >= 1; }")
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}
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#[test]
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fn flip_binexpr_works_for_complex_expr() {
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check_assist(
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flip_binexpr,
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"fn f() { let res = (1 + 1) ==$0 (2 + 2); }",
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"fn f() { let res = (2 + 2) == (1 + 1); }",
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)
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}
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#[test]
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fn flip_binexpr_works_inside_match() {
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check_assist(
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flip_binexpr,
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r#"
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fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
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match other.downcast_ref::<Self>() {
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None => false,
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Some(it) => it ==$0 self,
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}
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}
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"#,
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r#"
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fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
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match other.downcast_ref::<Self>() {
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None => false,
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Some(it) => self == it,
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}
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}
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"#,
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)
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}
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}
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