aboutsummaryrefslogtreecommitdiff
path: root/crates/syntax/src/ast/edit.rs
blob: 2663c0759d23091cd2b682f067f8e13589a8a85e (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
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
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
//! This module contains functions for editing syntax trees. As the trees are
//! immutable, all function here return a fresh copy of the tree, instead of
//! doing an in-place modification.
use std::{
    fmt, iter,
    ops::{self, RangeInclusive},
};

use crate::{
    algo,
    ast::{self, make, AstNode},
    ted, AstToken, NodeOrToken, SyntaxElement, SyntaxKind,
    SyntaxKind::{ATTR, COMMENT, WHITESPACE},
    SyntaxNode, SyntaxToken,
};

impl ast::BinExpr {
    #[must_use]
    pub fn replace_op(&self, op: SyntaxKind) -> Option<ast::BinExpr> {
        let op_node: SyntaxElement = self.op_details()?.0.into();
        let to_insert: Option<SyntaxElement> = Some(make::token(op).into());
        Some(self.replace_children(single_node(op_node), to_insert))
    }
}

impl ast::UseTree {
    /// Splits off the given prefix, making it the path component of the use tree, appending the rest of the path to all UseTreeList items.
    #[must_use]
    pub fn split_prefix(&self, prefix: &ast::Path) -> ast::UseTree {
        let suffix = if self.path().as_ref() == Some(prefix) && self.use_tree_list().is_none() {
            make::path_unqualified(make::path_segment_self())
        } else {
            match split_path_prefix(prefix) {
                Some(it) => it,
                None => return self.clone(),
            }
        };

        let use_tree = make::use_tree(
            suffix,
            self.use_tree_list(),
            self.rename(),
            self.star_token().is_some(),
        );
        let nested = make::use_tree_list(iter::once(use_tree));
        return make::use_tree(prefix.clone(), Some(nested), None, false);

        fn split_path_prefix(prefix: &ast::Path) -> Option<ast::Path> {
            let parent = prefix.parent_path()?;
            let segment = parent.segment()?;
            if algo::has_errors(segment.syntax()) {
                return None;
            }
            let mut res = make::path_unqualified(segment);
            for p in iter::successors(parent.parent_path(), |it| it.parent_path()) {
                res = make::path_qualified(res, p.segment()?);
            }
            Some(res)
        }
    }
}

#[must_use]
pub fn remove_attrs_and_docs<N: ast::AttrsOwner>(node: &N) -> N {
    N::cast(remove_attrs_and_docs_inner(node.syntax().clone())).unwrap()
}

fn remove_attrs_and_docs_inner(mut node: SyntaxNode) -> SyntaxNode {
    while let Some(start) =
        node.children_with_tokens().find(|it| it.kind() == ATTR || it.kind() == COMMENT)
    {
        let end = match &start.next_sibling_or_token() {
            Some(el) if el.kind() == WHITESPACE => el.clone(),
            Some(_) | None => start.clone(),
        };
        node = algo::replace_children(&node, start..=end, &mut iter::empty());
    }
    node
}

#[derive(Debug, Clone, Copy)]
pub struct IndentLevel(pub u8);

impl From<u8> for IndentLevel {
    fn from(level: u8) -> IndentLevel {
        IndentLevel(level)
    }
}

impl fmt::Display for IndentLevel {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let spaces = "                                        ";
        let buf;
        let len = self.0 as usize * 4;
        let indent = if len <= spaces.len() {
            &spaces[..len]
        } else {
            buf = " ".repeat(len);
            &buf
        };
        fmt::Display::fmt(indent, f)
    }
}

impl ops::Add<u8> for IndentLevel {
    type Output = IndentLevel;
    fn add(self, rhs: u8) -> IndentLevel {
        IndentLevel(self.0 + rhs)
    }
}

impl IndentLevel {
    pub fn single() -> IndentLevel {
        IndentLevel(0)
    }
    pub fn is_zero(&self) -> bool {
        self.0 == 0
    }
    pub fn from_element(element: &SyntaxElement) -> IndentLevel {
        match element {
            rowan::NodeOrToken::Node(it) => IndentLevel::from_node(it),
            rowan::NodeOrToken::Token(it) => IndentLevel::from_token(it),
        }
    }

    pub fn from_node(node: &SyntaxNode) -> IndentLevel {
        match node.first_token() {
            Some(it) => Self::from_token(&it),
            None => IndentLevel(0),
        }
    }

    pub fn from_token(token: &SyntaxToken) -> IndentLevel {
        for ws in prev_tokens(token.clone()).filter_map(ast::Whitespace::cast) {
            let text = ws.syntax().text();
            if let Some(pos) = text.rfind('\n') {
                let level = text[pos + 1..].chars().count() / 4;
                return IndentLevel(level as u8);
            }
        }
        IndentLevel(0)
    }

    /// XXX: this intentionally doesn't change the indent of the very first token.
    /// Ie, in something like
    /// ```
    /// fn foo() {
    ///    92
    /// }
    /// ```
    /// if you indent the block, the `{` token would stay put.
    fn increase_indent(self, node: SyntaxNode) -> SyntaxNode {
        let res = node.clone_subtree().clone_for_update();
        let tokens = res.preorder_with_tokens().filter_map(|event| match event {
            rowan::WalkEvent::Leave(NodeOrToken::Token(it)) => Some(it),
            _ => None,
        });
        for token in tokens {
            if let Some(ws) = ast::Whitespace::cast(token) {
                if ws.text().contains('\n') {
                    let new_ws = make::tokens::whitespace(&format!("{}{}", ws.syntax(), self));
                    ted::replace(ws.syntax(), &new_ws)
                }
            }
        }
        res.clone_subtree()
    }

    fn decrease_indent(self, node: SyntaxNode) -> SyntaxNode {
        let res = node.clone_subtree().clone_for_update();
        let tokens = res.preorder_with_tokens().filter_map(|event| match event {
            rowan::WalkEvent::Leave(NodeOrToken::Token(it)) => Some(it),
            _ => None,
        });
        for token in tokens {
            if let Some(ws) = ast::Whitespace::cast(token) {
                if ws.text().contains('\n') {
                    let new_ws = make::tokens::whitespace(
                        &ws.syntax().text().replace(&format!("\n{}", self), "\n"),
                    );
                    ted::replace(ws.syntax(), &new_ws)
                }
            }
        }
        res.clone_subtree()
    }
}

fn prev_tokens(token: SyntaxToken) -> impl Iterator<Item = SyntaxToken> {
    iter::successors(Some(token), |token| token.prev_token())
}

pub trait AstNodeEdit: AstNode + Clone + Sized {
    #[must_use]
    fn replace_children(
        &self,
        to_replace: RangeInclusive<SyntaxElement>,
        to_insert: impl IntoIterator<Item = SyntaxElement>,
    ) -> Self {
        let new_syntax = algo::replace_children(self.syntax(), to_replace, to_insert);
        Self::cast(new_syntax).unwrap()
    }
    fn indent_level(&self) -> IndentLevel {
        IndentLevel::from_node(self.syntax())
    }
    #[must_use]
    fn indent(&self, level: IndentLevel) -> Self {
        Self::cast(level.increase_indent(self.syntax().clone())).unwrap()
    }
    #[must_use]
    fn dedent(&self, level: IndentLevel) -> Self {
        Self::cast(level.decrease_indent(self.syntax().clone())).unwrap()
    }
    #[must_use]
    fn reset_indent(&self) -> Self {
        let level = IndentLevel::from_node(self.syntax());
        self.dedent(level)
    }
}

impl<N: AstNode + Clone> AstNodeEdit for N {}

fn single_node(element: impl Into<SyntaxElement>) -> RangeInclusive<SyntaxElement> {
    let element = element.into();
    element.clone()..=element
}

#[test]
fn test_increase_indent() {
    let arm_list = {
        let arm = make::match_arm(iter::once(make::wildcard_pat().into()), make::expr_unit());
        make::match_arm_list(vec![arm.clone(), arm])
    };
    assert_eq!(
        arm_list.syntax().to_string(),
        "{
    _ => (),
    _ => (),
}"
    );
    let indented = arm_list.indent(IndentLevel(2));
    assert_eq!(
        indented.syntax().to_string(),
        "{
            _ => (),
            _ => (),
        }"
    );
}