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
|
/// Machinery for macro expansion.
///
/// One of the more complicated things about macros is managing the source code
/// that is produced after expansion. See `HirFileId` and `MacroCallId` for how
/// do we do that.
///
/// When the file-management question is resolved, all that is left is a
/// token-tree-to-token-tree transformation plus hygiene. We don't have either of
/// those yet, so all macros are string based at the moment!
use std::sync::Arc;
use ra_syntax::{
TextRange, TextUnit, SourceFile, AstNode, SyntaxNode, TreeArc, SyntaxNodePtr,
ast,
};
use crate::{MacroCallId, PersistentHirDatabase};
// Hard-coded defs for now :-(
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum MacroDef {
Vec,
}
impl MacroDef {
/// Expands macro call, returning the expansion and offset to be used to
/// convert ranges between expansion and original source.
pub fn ast_expand(macro_call: &ast::MacroCall) -> Option<(TextUnit, MacroExpansion)> {
let (def, input) = MacroDef::from_call(macro_call)?;
let exp = def.expand(input)?;
let off = macro_call.token_tree()?.syntax().range().start();
Some((off, exp))
}
fn from_call(macro_call: &ast::MacroCall) -> Option<(MacroDef, MacroInput)> {
let def = {
let path = macro_call.path()?;
let name_ref = path.segment()?.name_ref()?;
if name_ref.text() == "vec" {
MacroDef::Vec
} else {
return None;
}
};
let input = {
let arg = macro_call.token_tree()?.syntax();
MacroInput { text: arg.text().to_string() }
};
Some((def, input))
}
fn expand(self, input: MacroInput) -> Option<MacroExpansion> {
match self {
MacroDef::Vec => self.expand_vec(input),
}
}
fn expand_vec(self, input: MacroInput) -> Option<MacroExpansion> {
let text = format!(r"fn dummy() {{ {}; }}", input.text);
let file = SourceFile::parse(&text);
let array_expr = file.syntax().descendants().find_map(ast::ArrayExpr::cast)?;
let ptr = SyntaxNodePtr::new(array_expr.syntax());
let src_range = TextRange::offset_len(0.into(), TextUnit::of_str(&input.text));
let ranges_map = vec![(src_range, array_expr.syntax().range())];
let res = MacroExpansion { text, ranges_map, ptr };
Some(res)
}
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct MacroInput {
// Should be token trees
pub text: String,
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct MacroExpansion {
/// The result of macro expansion. Should be token tree as well.
text: String,
/// Correspondence between ranges in the original source code and ranges in
/// the macro.
ranges_map: Vec<(TextRange, TextRange)>,
/// Implementation detail: internally, a macro is expanded to the whole file,
/// even if it is an expression. This `ptr` selects the actual expansion from
/// the expanded file.
ptr: SyntaxNodePtr,
}
impl MacroExpansion {
// FIXME: does not really make sense, macro expansion is not necessary a
// whole file. See `MacroExpansion::ptr` as well.
pub(crate) fn file(&self) -> TreeArc<SourceFile> {
SourceFile::parse(&self.text)
}
pub fn syntax(&self) -> TreeArc<SyntaxNode> {
self.ptr.to_node(&self.file()).to_owned()
}
/// Maps range in the source code to the range in the expanded code.
pub fn map_range_forward(&self, src_range: TextRange) -> Option<TextRange> {
for (s_range, t_range) in self.ranges_map.iter() {
if src_range.is_subrange(&s_range) {
let src_at_zero_range = src_range - src_range.start();
let src_range_offset = src_range.start() - s_range.start();
let src_range = src_at_zero_range + src_range_offset + t_range.start();
return Some(src_range);
}
}
None
}
/// Maps range in the expanded code to the range in the source code.
pub fn map_range_back(&self, tgt_range: TextRange) -> Option<TextRange> {
for (s_range, t_range) in self.ranges_map.iter() {
if tgt_range.is_subrange(&t_range) {
let tgt_at_zero_range = tgt_range - tgt_range.start();
let tgt_range_offset = tgt_range.start() - t_range.start();
let src_range = tgt_at_zero_range + tgt_range_offset + s_range.start();
return Some(src_range);
}
}
None
}
}
pub(crate) fn expand_macro_invocation(
db: &impl PersistentHirDatabase,
invoc: MacroCallId,
) -> Option<Arc<MacroExpansion>> {
let loc = invoc.loc(db);
let syntax = db.file_item(loc.source_item_id);
let macro_call = ast::MacroCall::cast(&syntax).unwrap();
let (def, input) = MacroDef::from_call(macro_call)?;
def.expand(input).map(Arc::new)
}
|
