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
250
251
252
253
254
255
256
257
use either::Either;
use crate::context::shared::Replacements;
use super::*;
impl TypleContext {
// Replace `T` with `(T0, T1,...)` and `T<1>` with `T1`
pub(super) fn replace_type(&self, ty: &mut Type) -> syn::Result<()> {
match ty {
Type::Array(array) => {
self.replace_type(&mut array.elem)?;
let mut state = BlockState::default();
self.replace_expr(&mut array.len, &mut state)?;
}
Type::BareFn(bare_fn) => {
bare_fn.inputs = std::mem::take(&mut bare_fn.inputs)
.into_iter()
.flat_map(|arg| {
self.replace_type_in_list(arg.ty).map(move |res| {
res.map(|ty| syn::BareFnArg {
attrs: arg.attrs.clone(),
name: arg.name.clone(),
ty,
})
})
})
.collect::<syn::Result<_>>()?;
if let ReturnType::Type(_, ty) = &mut bare_fn.output {
self.replace_type(ty)?;
}
}
Type::Group(group) => {
self.replace_type(&mut group.elem)?;
}
Type::Macro(m) => {
if let Some(typ) = self.replace_macro_type(m)? {
*ty = typ;
}
}
Type::Paren(paren) => {
match self.replace_type_in_list(std::mem::replace(
&mut paren.elem,
Type::Verbatim(TokenStream::new()),
)) {
Replacements::Singleton(Ok(inner)) => {
paren.elem = Box::new(inner);
}
iter => {
*ty = Type::Tuple(syn::TypeTuple {
paren_token: paren.paren_token,
elems: iter.collect::<syn::Result<_>>()?,
});
}
}
}
Type::Path(path) => {
self.replace_qself_path(&mut path.qself, &mut path.path)?;
if path.path.segments.is_empty() {
if let Some(qself) = path.qself.take() {
*ty = *qself.ty;
return Ok(());
}
}
self.replace_path_arguments(&mut path.path)?;
}
Type::Ptr(ptr) => {
self.replace_type(&mut ptr.elem)?;
}
Type::Reference(reference) => {
self.replace_type(&mut reference.elem)?;
}
Type::Slice(slice) => {
self.replace_type(&mut slice.elem)?;
}
Type::Tuple(tuple) => {
tuple.elems = std::mem::take(&mut tuple.elems)
.into_iter()
.flat_map(|ty| self.replace_type_in_list(ty))
.collect::<syn::Result<_>>()?;
}
_ => {}
}
Ok(())
}
pub(super) fn replace_type_in_list(
&self,
mut ty: Type,
) -> Replacements<impl Iterator<Item = syn::Result<Type>>> {
match &mut ty {
Type::Macro(syn::TypeMacro { mac }) => {
if let Some(ident) = mac.path.get_ident() {
if ident == "typle" {
let token_stream = std::mem::take(&mut mac.tokens);
return self
.expand_typle_macro(token_stream, |context, token_stream| {
Ok(Replacements::Iterator(
Punctuated::<syn::Type, token::Comma>::parse_terminated
.parse2(token_stream)?
.into_iter()
.map(|mut ty| {
context.replace_type(&mut ty)?;
Ok(ty)
})
// collect and into_iter due to context lifetime
.collect::<Vec<_>>()
.into_iter(),
))
})
.map_iterator(Either::Left);
}
}
}
Type::Path(syn::TypePath { qself, path })
if qself.is_none() && path.leading_colon.is_none() =>
{
let mut segments = path.segments.iter_mut();
if let Some(first) = segments.next() {
if let (Some(typle), PathArguments::AngleBracketed(arguments), None) = (
self.typles.get(&first.ident),
&mut first.arguments,
segments.next(),
) {
let mut iter = arguments.args.iter_mut().fuse();
if let (Some(GenericArgument::Const(ref mut expr)), None) =
(iter.next(), iter.next())
{
let mut state = BlockState::default();
if let Err(err) = self.replace_expr(expr, &mut state) {
return Replacements::Singleton(Err(err));
}
if let Some((start, end)) = evaluate_range(expr) {
// T<{..}>
let start = match start {
Bound::Included(Err(span)) | Bound::Excluded(Err(span)) => {
return Replacements::Singleton(Err(syn::Error::new(
span,
"expected integer for start of range",
)));
}
Bound::Included(Ok(start)) => start,
Bound::Excluded(Ok(start)) => start.saturating_add(1),
Bound::Unbounded => 0,
};
let end = match end {
Bound::Included(Err(span)) | Bound::Excluded(Err(span)) => {
return Replacements::Singleton(Err(syn::Error::new(
span,
"expected integer for end of range",
)));
}
Bound::Included(Ok(end)) => end.saturating_add(1),
Bound::Excluded(Ok(end)) => end,
Bound::Unbounded => match self.typle_len {
Some(end) => end,
None => {
return Replacements::Singleton(Err(syn::Error::new(
expr.span(),
"need an explicit range end",
)));
}
},
};
return Replacements::Iterator(Either::Right((start..end).map({
let span = path.span();
let context = self.clone();
let typle = typle.clone();
move |i| context.get_type(&typle, i, span)
})));
}
}
}
}
}
_ => {}
}
match self.replace_type(&mut ty) {
Ok(()) => Replacements::Singleton(Ok(ty)),
Err(e) => Replacements::Singleton(Err(e)),
}
}
fn replace_macro_type(&self, m: &mut syn::TypeMacro) -> syn::Result<Option<Type>> {
// (typle! {i in .. => Option<T<{i}>}) -> (Option<T0>, Option<T1>)
// (typle! {i in .. => T::<{i}>::default()}) -> (T0::default(), T1::default())
// as opposed to
// Option<T> -> Option<(T0, T1)>
// T::default() -> <(T0, T1)>::default()
if let Some(macro_name) = m.mac.path.get_ident() {
if macro_name == "typle" {
let token_stream = std::mem::take(&mut m.mac.tokens);
// This is outside a comma-separated sequence so only no-range form is accepted
// typle!(=> if T::LEN == 0 {} else {})
return self.expand_typle_macro_singleton(token_stream, |context, token_stream| {
let mut ty = syn::parse2::<Type>(token_stream)?;
context.replace_type(&mut ty)?;
Ok(Some(ty))
});
} else if macro_name == "typle_fold" {
let default_span = macro_name.span();
let ty = self.replace_typle_fold_type(&mut m.mac, default_span)?;
return Ok(Some(ty));
}
}
m.mac.tokens = self.replace_macro_token_stream(std::mem::take(&mut m.mac.tokens))?;
Ok(None)
}
fn replace_typle_fold_type(&self, mac: &mut Macro, default_span: Span) -> syn::Result<Type> {
let token_stream = std::mem::take(&mut mac.tokens);
let mut tokens = token_stream.into_iter();
let mut init_type =
syn::parse2::<Type>(Self::extract_to_semicolon(&mut tokens, default_span)?)?;
self.replace_type(&mut init_type)?;
let Some((pattern, mut range)) = self.parse_pattern_range(&mut tokens)? else {
abort!(default_span, "typle_fold! must have range")
};
if range.is_empty() {
return Ok(init_type);
}
let folded_type = if let Some(last_index) = range.next_back() {
let fold_ident = Self::parse_fold_ident(&mut tokens, default_span)?;
let wrapping_type = syn::parse2::<Type>(tokens.collect())?;
let mut context = self.clone();
if let Some(ident) = &pattern {
context.constants.insert(ident.clone(), 0);
}
context.retypes.insert(
fold_ident.clone(),
Type::Verbatim(init_type.into_token_stream()),
);
for index in range {
if let Some(ident) = &pattern {
*context.constants.get_mut(ident).unwrap() = index;
}
let mut folded_type = wrapping_type.clone();
context.replace_type(&mut folded_type)?;
// retypes get cloned when they are inserted. This type can grow into
// a large nested type that is expensive to clone. Encoding the type
// as a verbatim TokenStream allows faster cloning. The type has had
// replacements done at this point so we do not need the structure.
*context.retypes.get_mut(&fold_ident).unwrap() =
Type::Verbatim(folded_type.into_token_stream());
}
if let Some(ident) = &pattern {
*context.constants.get_mut(ident).unwrap() = last_index;
}
let mut folded_type = wrapping_type;
context.replace_type(&mut folded_type)?;
folded_type
} else {
init_type
};
Ok(folded_type)
}
}