diff options
Diffstat (limited to 'crates/ra_assists/src/assists/invert_if.rs')
-rw-r--r-- | crates/ra_assists/src/assists/invert_if.rs | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/crates/ra_assists/src/assists/invert_if.rs b/crates/ra_assists/src/assists/invert_if.rs new file mode 100644 index 000000000..bababa3e2 --- /dev/null +++ b/crates/ra_assists/src/assists/invert_if.rs | |||
@@ -0,0 +1,102 @@ | |||
1 | use hir::db::HirDatabase; | ||
2 | use ra_syntax::ast::{self, AstNode}; | ||
3 | use ra_syntax::T; | ||
4 | |||
5 | use crate::{Assist, AssistCtx, AssistId}; | ||
6 | |||
7 | // Assist: invert_if | ||
8 | // | ||
9 | // Apply invert_if | ||
10 | // This transforms if expressions of the form `if !x {A} else {B}` into `if x {B} else {A}` | ||
11 | // This also works with `!=`. This assist can only be applied with the cursor | ||
12 | // on `if`. | ||
13 | // | ||
14 | // ``` | ||
15 | // fn main() { | ||
16 | // if<|> !y { A } else { B } | ||
17 | // } | ||
18 | // ``` | ||
19 | // -> | ||
20 | // ``` | ||
21 | // fn main() { | ||
22 | // if y { B } else { A } | ||
23 | // } | ||
24 | // ``` | ||
25 | |||
26 | pub(crate) fn invert_if(ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> { | ||
27 | let if_keyword = ctx.find_token_at_offset(T![if])?; | ||
28 | let expr = ast::IfExpr::cast(if_keyword.parent())?; | ||
29 | let if_range = if_keyword.text_range(); | ||
30 | let cursor_in_range = ctx.frange.range.is_subrange(&if_range); | ||
31 | if !cursor_in_range { | ||
32 | return None; | ||
33 | } | ||
34 | |||
35 | let cond = expr.condition()?.expr()?; | ||
36 | let then_node = expr.then_branch()?.syntax().clone(); | ||
37 | |||
38 | if let ast::ElseBranch::Block(else_block) = expr.else_branch()? { | ||
39 | let flip_cond = invert_boolean_expression(&cond)?; | ||
40 | let cond_range = cond.syntax().text_range(); | ||
41 | let else_node = else_block.syntax(); | ||
42 | let else_range = else_node.text_range(); | ||
43 | let then_range = then_node.text_range(); | ||
44 | return ctx.add_assist(AssistId("invert_if"), "invert if branches", |edit| { | ||
45 | edit.target(if_range); | ||
46 | edit.replace(cond_range, flip_cond.syntax().text()); | ||
47 | edit.replace(else_range, then_node.text()); | ||
48 | edit.replace(then_range, else_node.text()); | ||
49 | }); | ||
50 | } | ||
51 | |||
52 | None | ||
53 | } | ||
54 | |||
55 | pub(crate) fn invert_boolean_expression(expr: &ast::Expr) -> Option<ast::Expr> { | ||
56 | match expr { | ||
57 | ast::Expr::BinExpr(bin) => match bin.op_kind()? { | ||
58 | ast::BinOp::NegatedEqualityTest => bin.replace_op(T![==]).map(|it| it.into()), | ||
59 | _ => None, | ||
60 | }, | ||
61 | ast::Expr::PrefixExpr(pe) => match pe.op_kind()? { | ||
62 | ast::PrefixOp::Not => pe.expr(), | ||
63 | _ => None, | ||
64 | }, | ||
65 | _ => None, | ||
66 | } | ||
67 | } | ||
68 | |||
69 | #[cfg(test)] | ||
70 | mod tests { | ||
71 | use super::*; | ||
72 | |||
73 | use crate::helpers::{check_assist, check_assist_not_applicable}; | ||
74 | |||
75 | #[test] | ||
76 | fn invert_if_remove_inequality() { | ||
77 | check_assist( | ||
78 | invert_if, | ||
79 | "fn f() { i<|>f x != 3 { 1 } else { 3 + 2 } }", | ||
80 | "fn f() { i<|>f x == 3 { 3 + 2 } else { 1 } }", | ||
81 | ) | ||
82 | } | ||
83 | |||
84 | #[test] | ||
85 | fn invert_if_remove_not() { | ||
86 | check_assist( | ||
87 | invert_if, | ||
88 | "fn f() { <|>if !cond { 3 * 2 } else { 1 } }", | ||
89 | "fn f() { <|>if cond { 1 } else { 3 * 2 } }", | ||
90 | ) | ||
91 | } | ||
92 | |||
93 | #[test] | ||
94 | fn invert_if_doesnt_apply_with_cursor_not_on_if() { | ||
95 | check_assist_not_applicable(invert_if, "fn f() { if !<|>cond { 3 * 2 } else { 1 } }") | ||
96 | } | ||
97 | |||
98 | #[test] | ||
99 | fn invert_if_doesnt_apply_without_negated() { | ||
100 | check_assist_not_applicable(invert_if, "fn f() { i<|>f cond { 3 * 2 } else { 1 } }") | ||
101 | } | ||
102 | } | ||