142 lines
4.2 KiB
Rust
142 lines
4.2 KiB
Rust
use hir::db::HirDatabase;
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use ra_syntax::ast::{AstNode, BinExpr, BinOp};
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use crate::{AssistCtx, Assist, AssistId};
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/// Flip binary expression assist.
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pub(crate) fn flip_binexpr(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
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let expr = ctx.node_at_offset::<BinExpr>()?;
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let lhs = expr.lhs()?.syntax();
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let rhs = expr.rhs()?.syntax();
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let op_range = expr.op_token()?.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 = ctx.frange.range.is_subrange(&op_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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ctx.add_action(AssistId("flip_binexpr"), "flip binary expression", |edit| {
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edit.target(op_range);
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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.range(), rhs.text());
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edit.replace(rhs.range(), lhs.text());
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});
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ctx.build()
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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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BinOp::Assignment => FlipAction::DontFlip,
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BinOp::AddAssign => FlipAction::DontFlip,
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BinOp::DivAssign => FlipAction::DontFlip,
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BinOp::MulAssign => FlipAction::DontFlip,
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BinOp::RemAssign => FlipAction::DontFlip,
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BinOp::ShrAssign => FlipAction::DontFlip,
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BinOp::ShlAssign => FlipAction::DontFlip,
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BinOp::SubAssign => FlipAction::DontFlip,
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BinOp::BitOrAssign => FlipAction::DontFlip,
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BinOp::BitAndAssign => FlipAction::DontFlip,
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BinOp::BitXorAssign => 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::helpers::{ check_assist, check_assist_target, check_assist_not_applicable };
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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 ==<|> 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 +=<|> 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(
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flip_binexpr,
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"fn f() { let res = 1 ==<|> 2; }",
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"fn f() { let res = 2 ==<|> 1; }",
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)
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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(
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flip_binexpr,
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"fn f() { let res = 1 ><|> 2; }",
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"fn f() { let res = 2 <<|> 1; }",
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)
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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(
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flip_binexpr,
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"fn f() { let res = 1 <=<|> 2; }",
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"fn f() { let res = 2 >=<|> 1; }",
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)
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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) ==<|> (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 ==<|> 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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