1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
use syntax::ast::{self, AstNode};
use crate::{utils::invert_boolean_expression, AssistContext, AssistId, AssistKind, Assists};
// Assist: apply_demorgan
//
// Apply https://en.wikipedia.org/wiki/De_Morgan%27s_laws[De Morgan's law].
// This transforms expressions of the form `!l || !r` into `!(l && r)`.
// This also works with `&&`. This assist can only be applied with the cursor
// on either `||` or `&&`.
//
// ```
// fn main() {
// if x != 4 ||$0 y < 3.14 {}
// }
// ```
// ->
// ```
// fn main() {
// if !(x == 4 && !(y < 3.14)) {}
// }
// ```
pub(crate) fn apply_demorgan(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let expr = ctx.find_node_at_offset::<ast::BinExpr>()?;
let op = expr.op_kind()?;
let op_range = expr.op_token()?.text_range();
let opposite_op = opposite_logic_op(op)?;
let cursor_in_range = op_range.contains_range(ctx.frange.range);
if !cursor_in_range {
return None;
}
let lhs = expr.lhs()?;
let lhs_range = lhs.syntax().text_range();
let not_lhs = invert_boolean_expression(&ctx.sema, lhs);
let rhs = expr.rhs()?;
let rhs_range = rhs.syntax().text_range();
let not_rhs = invert_boolean_expression(&ctx.sema, rhs);
acc.add(
AssistId("apply_demorgan", AssistKind::RefactorRewrite),
"Apply De Morgan's law",
op_range,
|edit| {
let paren_expr = expr.syntax().parent().and_then(|parent| ast::ParenExpr::cast(parent));
let neg_expr = paren_expr
.clone()
.and_then(|paren_expr| paren_expr.syntax().parent())
.and_then(|parent| ast::PrefixExpr::cast(parent))
.and_then(|prefix_expr| {
if prefix_expr.op_kind().unwrap() == ast::PrefixOp::Not {
Some(prefix_expr)
} else {
None
}
});
edit.replace(op_range, opposite_op);
if let Some(paren_expr) = paren_expr {
edit.replace(lhs_range, not_lhs.syntax().text());
edit.replace(rhs_range, not_rhs.syntax().text());
if let Some(neg_expr) = neg_expr {
cov_mark::hit!(demorgan_double_negation);
edit.replace(neg_expr.op_token().unwrap().text_range(), "");
} else {
cov_mark::hit!(demorgan_double_parens);
edit.replace(paren_expr.l_paren_token().unwrap().text_range(), "!(");
}
} else {
edit.replace(lhs_range, format!("!({}", not_lhs.syntax().text()));
edit.replace(rhs_range, format!("{})", not_rhs.syntax().text()));
}
},
)
}
// Return the opposite text for a given logical operator, if it makes sense
fn opposite_logic_op(kind: ast::BinOp) -> Option<&'static str> {
match kind {
ast::BinOp::BooleanOr => Some("&&"),
ast::BinOp::BooleanAnd => Some("||"),
_ => None,
}
}
#[cfg(test)]
mod tests {
use ide_db::helpers::FamousDefs;
use super::*;
use crate::tests::{check_assist, check_assist_not_applicable};
const ORDABLE_FIXTURE: &'static str = r"
//- /lib.rs deps:core crate:ordable
struct NonOrderable;
struct Orderable;
impl core::cmp::Ord for Orderable {}
";
fn check(ra_fixture_before: &str, ra_fixture_after: &str) {
let before = &format!(
"//- /main.rs crate:main deps:core,ordable\n{}\n{}{}",
ra_fixture_before,
FamousDefs::FIXTURE,
ORDABLE_FIXTURE
);
check_assist(apply_demorgan, before, &format!("{}\n", ra_fixture_after));
}
#[test]
fn demorgan_handles_leq() {
check(
r"use ordable::Orderable;
fn f() {
Orderable < Orderable &&$0 Orderable <= Orderable
}",
r"use ordable::Orderable;
fn f() {
!(Orderable >= Orderable || Orderable > Orderable)
}",
);
check(
r"use ordable::NonOrderable;
fn f() {
NonOrderable < NonOrderable &&$0 NonOrderable <= NonOrderable
}",
r"use ordable::NonOrderable;
fn f() {
!(!(NonOrderable < NonOrderable) || !(NonOrderable <= NonOrderable))
}",
);
}
#[test]
fn demorgan_handles_geq() {
check(
r"use ordable::Orderable;
fn f() {
Orderable > Orderable &&$0 Orderable >= Orderable
}",
r"use ordable::Orderable;
fn f() {
!(Orderable <= Orderable || Orderable < Orderable)
}",
);
check(
r"use ordable::NonOrderable;
fn f() {
Orderable > Orderable &&$0 Orderable >= Orderable
}",
r"use ordable::NonOrderable;
fn f() {
!(!(Orderable > Orderable) || !(Orderable >= Orderable))
}",
);
}
#[test]
fn demorgan_turns_and_into_or() {
check_assist(apply_demorgan, "fn f() { !x &&$0 !x }", "fn f() { !(x || x) }")
}
#[test]
fn demorgan_turns_or_into_and() {
check_assist(apply_demorgan, "fn f() { !x ||$0 !x }", "fn f() { !(x && x) }")
}
#[test]
fn demorgan_removes_inequality() {
check_assist(apply_demorgan, "fn f() { x != x ||$0 !x }", "fn f() { !(x == x && x) }")
}
#[test]
fn demorgan_general_case() {
check_assist(apply_demorgan, "fn f() { x ||$0 x }", "fn f() { !(!x && !x) }")
}
#[test]
fn demorgan_doesnt_apply_with_cursor_not_on_op() {
check_assist_not_applicable(apply_demorgan, "fn f() { $0 !x || !x }")
}
#[test]
fn demorgan_doesnt_double_negation() {
cov_mark::check!(demorgan_double_negation);
check_assist(apply_demorgan, "fn f() { !(x ||$0 x) }", "fn f() { (!x && !x) }")
}
#[test]
fn demorgan_doesnt_double_parens() {
cov_mark::check!(demorgan_double_parens);
check_assist(apply_demorgan, "fn f() { (x ||$0 x) }", "fn f() { !(!x && !x) }")
}
}
|
