aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_editor/src/assists/introduce_variable.rs
blob: 17ab521facd4cc322608da3697134321a47c820f (plain)
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
use ra_text_edit::TextEditBuilder;
use ra_syntax::{
    algo::{find_covering_node},
    ast::{self, AstNode},
    SourceFileNode,
    SyntaxKind::{WHITESPACE},
    SyntaxNodeRef, TextRange, TextUnit,
};

use crate::assists::LocalEdit;

pub fn introduce_variable<'a>(
    file: &'a SourceFileNode,
    range: TextRange,
) -> Option<impl FnOnce() -> LocalEdit + 'a> {
    let node = find_covering_node(file.syntax(), range);
    let expr = node.ancestors().filter_map(ast::Expr::cast).next()?;

    let anchor_stmt = anchor_stmt(expr)?;
    let indent = anchor_stmt.prev_sibling()?;
    if indent.kind() != WHITESPACE {
        return None;
    }
    return Some(move || {
        let mut buf = String::new();
        let mut edit = TextEditBuilder::new();

        buf.push_str("let var_name = ");
        expr.syntax().text().push_to(&mut buf);
        let is_full_stmt = if let Some(expr_stmt) = ast::ExprStmt::cast(anchor_stmt) {
            Some(expr.syntax()) == expr_stmt.expr().map(|e| e.syntax())
        } else {
            false
        };
        if is_full_stmt {
            edit.replace(expr.syntax().range(), buf);
        } else {
            buf.push_str(";");
            indent.text().push_to(&mut buf);
            edit.replace(expr.syntax().range(), "var_name".to_string());
            edit.insert(anchor_stmt.range().start(), buf);
        }
        let cursor_position = anchor_stmt.range().start() + TextUnit::of_str("let ");
        LocalEdit {
            label: "introduce variable".to_string(),
            edit: edit.finish(),
            cursor_position: Some(cursor_position),
        }
    });

    /// Statement or last in the block expression, which will follow
    /// the freshly introduced var.
    fn anchor_stmt(expr: ast::Expr) -> Option<SyntaxNodeRef> {
        expr.syntax().ancestors().find(|&node| {
            if ast::Stmt::cast(node).is_some() {
                return true;
            }
            if let Some(expr) = node
                .parent()
                .and_then(ast::Block::cast)
                .and_then(|it| it.expr())
            {
                if expr.syntax() == node {
                    return true;
                }
            }
            false
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::test_utils::check_action_range;

    #[test]
    fn test_introduce_var_simple() {
        check_action_range(
            "
fn foo() {
    foo(<|>1 + 1<|>);
}",
            "
fn foo() {
    let <|>var_name = 1 + 1;
    foo(var_name);
}",
            |file, range| introduce_variable(file, range).map(|f| f()),
        );
    }

    #[test]
    fn test_introduce_var_expr_stmt() {
        check_action_range(
            "
fn foo() {
    <|>1 + 1<|>;
}",
            "
fn foo() {
    let <|>var_name = 1 + 1;
}",
            |file, range| introduce_variable(file, range).map(|f| f()),
        );
    }

    #[test]
    fn test_introduce_var_part_of_expr_stmt() {
        check_action_range(
            "
fn foo() {
    <|>1<|> + 1;
}",
            "
fn foo() {
    let <|>var_name = 1;
    var_name + 1;
}",
            |file, range| introduce_variable(file, range).map(|f| f()),
        );
    }

    #[test]
    fn test_introduce_var_last_expr() {
        check_action_range(
            "
fn foo() {
    bar(<|>1 + 1<|>)
}",
            "
fn foo() {
    let <|>var_name = 1 + 1;
    bar(var_name)
}",
            |file, range| introduce_variable(file, range).map(|f| f()),
        );
    }

    #[test]
    fn test_introduce_var_last_full_expr() {
        check_action_range(
            "
fn foo() {
    <|>bar(1 + 1)<|>
}",
            "
fn foo() {
    let <|>var_name = bar(1 + 1);
    var_name
}",
            |file, range| introduce_variable(file, range).map(|f| f()),
        );
    }

}