aboutsummaryrefslogtreecommitdiff
path: root/crates/syntax/src/ted.rs
blob: be2b846b1513f5eb7dbba212eaed621c60932869 (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
//! Primitive tree editor, ed for trees.
//!
//! The `_raw`-suffixed functions insert elements as is, unsuffixed versions fix
//! up elements around the edges.
use std::ops::RangeInclusive;

use parser::T;

use crate::{ast::make, SyntaxElement, SyntaxKind, SyntaxNode, SyntaxToken};

/// Utility trait to allow calling `ted` functions with references or owned
/// nodes. Do not use outside of this module.
pub trait Element {
    fn syntax_element(self) -> SyntaxElement;
}

impl<E: Element + Clone> Element for &'_ E {
    fn syntax_element(self) -> SyntaxElement {
        self.clone().syntax_element()
    }
}
impl Element for SyntaxElement {
    fn syntax_element(self) -> SyntaxElement {
        self
    }
}
impl Element for SyntaxNode {
    fn syntax_element(self) -> SyntaxElement {
        self.into()
    }
}
impl Element for SyntaxToken {
    fn syntax_element(self) -> SyntaxElement {
        self.into()
    }
}

#[derive(Debug)]
pub struct Position {
    repr: PositionRepr,
}

#[derive(Debug)]
enum PositionRepr {
    FirstChild(SyntaxNode),
    After(SyntaxElement),
}

impl Position {
    pub fn after(elem: impl Element) -> Position {
        let repr = PositionRepr::After(elem.syntax_element());
        Position { repr }
    }
    pub fn before(elem: impl Element) -> Position {
        let elem = elem.syntax_element();
        let repr = match elem.prev_sibling_or_token() {
            Some(it) => PositionRepr::After(it),
            None => PositionRepr::FirstChild(elem.parent().unwrap()),
        };
        Position { repr }
    }
    pub fn first_child_of(node: &(impl Into<SyntaxNode> + Clone)) -> Position {
        let repr = PositionRepr::FirstChild(node.clone().into());
        Position { repr }
    }
    pub fn last_child_of(node: &(impl Into<SyntaxNode> + Clone)) -> Position {
        let node = node.clone().into();
        let repr = match node.last_child_or_token() {
            Some(it) => PositionRepr::After(it),
            None => PositionRepr::FirstChild(node),
        };
        Position { repr }
    }
}

pub fn insert(position: Position, elem: impl Element) {
    insert_all(position, vec![elem.syntax_element()])
}
pub fn insert_raw(position: Position, elem: impl Element) {
    insert_all_raw(position, vec![elem.syntax_element()])
}
pub fn insert_all(position: Position, mut elements: Vec<SyntaxElement>) {
    if let Some(first) = elements.first() {
        if let Some(ws) = ws_before(&position, first) {
            elements.insert(0, ws.into())
        }
    }
    if let Some(last) = elements.last() {
        if let Some(ws) = ws_after(&position, last) {
            elements.push(ws.into())
        }
    }
    insert_all_raw(position, elements)
}
pub fn insert_all_raw(position: Position, elements: Vec<SyntaxElement>) {
    let (parent, index) = match position.repr {
        PositionRepr::FirstChild(parent) => (parent, 0),
        PositionRepr::After(child) => (child.parent().unwrap(), child.index() + 1),
    };
    parent.splice_children(index..index, elements);
}

pub fn remove(elem: impl Element) {
    let elem = elem.syntax_element();
    remove_all(elem.clone()..=elem)
}
pub fn remove_all(range: RangeInclusive<SyntaxElement>) {
    replace_all(range, Vec::new())
}

pub fn replace(old: impl Element, new: impl Element) {
    let old = old.syntax_element();
    replace_all(old.clone()..=old, vec![new.syntax_element()])
}
pub fn replace_all(range: RangeInclusive<SyntaxElement>, new: Vec<SyntaxElement>) {
    let start = range.start().index();
    let end = range.end().index();
    let parent = range.start().parent().unwrap();
    parent.splice_children(start..end + 1, new)
}

pub fn append_child(node: &(impl Into<SyntaxNode> + Clone), child: impl Element) {
    let position = Position::last_child_of(node);
    insert(position, child)
}
pub fn append_child_raw(node: &(impl Into<SyntaxNode> + Clone), child: impl Element) {
    let position = Position::last_child_of(node);
    insert_raw(position, child)
}

fn ws_before(position: &Position, new: &SyntaxElement) -> Option<SyntaxToken> {
    let prev = match &position.repr {
        PositionRepr::FirstChild(_) => return None,
        PositionRepr::After(it) => it,
    };
    ws_between(prev, new)
}
fn ws_after(position: &Position, new: &SyntaxElement) -> Option<SyntaxToken> {
    let next = match &position.repr {
        PositionRepr::FirstChild(parent) => parent.first_child_or_token()?,
        PositionRepr::After(sibling) => sibling.next_sibling_or_token()?,
    };
    ws_between(new, &next)
}
fn ws_between(left: &SyntaxElement, right: &SyntaxElement) -> Option<SyntaxToken> {
    if left.kind() == SyntaxKind::WHITESPACE || right.kind() == SyntaxKind::WHITESPACE {
        return None;
    }
    if right.kind() == T![;] || right.kind() == T![,] {
        return None;
    }
    Some(make::tokens::single_space())
}