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
|
use proc_macro::TokenStream;
use quote::quote;
use syn::{Expr, Pat, Token, parse::{Parse, ParseStream, Result}, parse_macro_input};
struct ExternBlock {
pattern: Pat,
_arrow: Token![->],
return_ty: Expr,
_fat_arrow: Token![=>],
block: Expr,
_comma: Token![,],
}
struct ExternFunction {
function: syn::Ident,
blocks: Vec<ExternBlock>
}
impl Parse for ExternBlock {
fn parse(input: ParseStream) -> Result<Self> {
Ok(Self {
pattern: input.parse()?,
_arrow: input.parse()?,
return_ty: input.parse()?,
_fat_arrow: input.parse()?,
block: input.parse()?,
_comma: input.parse()?,
})
}
}
impl Parse for ExternFunction {
fn parse(input: ParseStream) -> Result<Self> {
let mut res = Self {
function: input.parse()?,
blocks: Vec::new(),
};
while !input.is_empty() {
res.blocks.push(input.parse()?);
}
Ok(res)
}
}
#[proc_macro]
pub fn extern_function(tokens: TokenStream) -> TokenStream {
let parsed: ExternFunction = parse_macro_input!(tokens);
let function = parsed.function;
let typecheck_blocks: Vec<_> = parsed.blocks.iter().map(|block| {
let pat = block.pattern.clone();
let ty = block.return_ty.clone();
quote! {
#pat => { Ok(sylt::Value::from(#ty)) }
}
}).collect();
let eval_blocks: Vec<_> = parsed.blocks.iter().map(|block| {
let pat = block.pattern.clone();
let expr = block.block.clone();
quote! {
#pat => #expr
}
}).collect();
let tokens = quote! {
pub fn #function (
__values: &[sylt::Value],
__typecheck: bool
) -> ::std::result::Result<sylt::Value, sylt::error::ErrorKind>
{
if __typecheck {
#[allow(unused_variables)]
match __values {
#(#typecheck_blocks),*
_ => Err(sylt::error::ErrorKind::ExternTypeMismatch(
stringify!(#function).to_string(),
__values.iter().map(|v| sylt::Type::from(v)).collect()
))
}
} else {
match __values {
#(#eval_blocks),*
_ => Err(sylt::error::ErrorKind::ExternTypeMismatch(
stringify!(#function).to_string(),
__values.iter().map(|v| sylt::Type::from(v)).collect()
))
}
}
}
};
TokenStream::from(tokens)
}
struct LinkRename {
_as: Token![as],
name: syn::Ident,
}
impl Parse for LinkRename {
fn parse(input: ParseStream) -> Result<Self> {
Ok(Self {
_as: input.parse()?,
name: input.parse()?,
})
}
}
struct Link {
path: syn::Path,
rename: Option<LinkRename>,
}
impl Parse for Link {
fn parse(input: ParseStream) -> Result<Self> {
Ok(Self {
path: input.parse()?,
rename: input.parse().ok(),
})
}
}
struct Links {
links: Vec<Link>,
}
impl Parse for Links {
fn parse(input: ParseStream) -> Result<Self> {
let mut res = Self {
links: Vec::new(),
};
while !input.is_empty() {
res.links.push(input.parse()?);
let _comma: Option<Token![,]> = input.parse().ok();
}
Ok(res)
}
}
#[proc_macro]
pub fn link(tokens: TokenStream) -> TokenStream {
let links: Links = parse_macro_input!(tokens);
let links: Vec<_> = links.links.iter().map(|link| {
let name = if let Some(rename) = &link.rename {
&rename.name
} else {
&link.path.segments.last().unwrap().ident
};
let path = &link.path;
quote! {
(stringify!(#name).to_string(), #path)
}
}).collect();
let tokens = quote! {
vec![ #(#links),* ]
};
TokenStream::from(tokens)
}
|
