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
|
diff --git a/Cargo.toml b/Cargo.toml
index 2e33871..388f042 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,8 +24,6 @@ repository = "https://git.sr.ht/~ireas/merge-rs/tree/master/merge_derive"
[lib]
proc-macro = true
-[dependencies.proc-macro-error]
-version = "1.0"
[dependencies.proc-macro2]
version = "1.0"
@@ -34,4 +32,4 @@ version = "1.0"
version = "1.0"
[dependencies.syn]
-version = "1.0"
+version = "2.0"
diff --git a/src/lib.rs b/src/lib.rs
index 75732f9..11f5b49 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -11,9 +11,9 @@
extern crate proc_macro;
use proc_macro2::TokenStream;
-use proc_macro_error::{abort, abort_call_site, dummy::set_dummy, proc_macro_error, ResultExt};
use quote::{quote, quote_spanned};
-use syn::Token;
+use std::convert::TryFrom;
+use syn::{Error, Result, Token};
struct Field {
name: syn::Member,
@@ -33,48 +33,51 @@ enum FieldAttr {
}
#[proc_macro_derive(Merge, attributes(merge))]
-#[proc_macro_error]
pub fn merge_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let ast = syn::parse(input).unwrap();
- impl_merge(&ast).into()
+ impl_merge(&ast)
+ .unwrap_or_else(Error::into_compile_error)
+ .into()
}
-fn impl_merge(ast: &syn::DeriveInput) -> TokenStream {
+fn impl_merge(ast: &syn::DeriveInput) -> Result<TokenStream> {
let name = &ast.ident;
- set_dummy(quote! {
- impl ::merge::Merge for #name {
- fn merge(&mut self, other: Self) {
- unimplemented!()
- }
- }
- });
-
if let syn::Data::Struct(syn::DataStruct { ref fields, .. }) = ast.data {
impl_merge_for_struct(name, fields)
} else {
- abort_call_site!("merge::Merge can only be derived for structs")
+ Err(Error::new_spanned(
+ ast,
+ "merge::Merge can only be derived for structs",
+ ))
}
}
-fn impl_merge_for_struct(name: &syn::Ident, fields: &syn::Fields) -> TokenStream {
- let assignments = gen_assignments(fields);
+fn impl_merge_for_struct(name: &syn::Ident, fields: &syn::Fields) -> Result<TokenStream> {
+ let assignments = gen_assignments(fields)?;
- quote! {
+ Ok(quote! {
impl ::merge::Merge for #name {
fn merge(&mut self, other: Self) {
#assignments
}
}
- }
+ })
}
-fn gen_assignments(fields: &syn::Fields) -> TokenStream {
- let fields = fields.iter().enumerate().map(Field::from);
- let assignments = fields.filter(|f| !f.attrs.skip).map(|f| gen_assignment(&f));
- quote! {
+fn gen_assignments(fields: &syn::Fields) -> Result<TokenStream> {
+ let fields = fields
+ .iter()
+ .enumerate()
+ .map(Field::try_from)
+ .collect::<Result<Vec<_>>>()?;
+ let assignments = fields
+ .iter()
+ .filter(|f| !f.attrs.skip)
+ .map(|f| gen_assignment(&f));
+ Ok(quote! {
#( #assignments )*
- }
+ })
}
fn gen_assignment(field: &Field) -> TokenStream {
@@ -88,48 +91,48 @@ fn gen_assignment(field: &Field) -> TokenStream {
}
}
-impl From<(usize, &syn::Field)> for Field {
- fn from(data: (usize, &syn::Field)) -> Self {
+impl TryFrom<(usize, &syn::Field)> for Field {
+ type Error = syn::Error;
+
+ fn try_from(data: (usize, &syn::Field)) -> std::result::Result<Self, Self::Error> {
use syn::spanned::Spanned;
let (index, field) = data;
- Field {
+ Ok(Field {
name: if let Some(ident) = &field.ident {
syn::Member::Named(ident.clone())
} else {
syn::Member::Unnamed(index.into())
},
span: field.span(),
- attrs: field.attrs.iter().into(),
- }
+ attrs: FieldAttrs::new(field.attrs.iter())?,
+ })
}
}
impl FieldAttrs {
- fn apply(&mut self, attr: FieldAttr) {
- match attr {
- FieldAttr::Skip => self.skip = true,
- FieldAttr::Strategy(path) => self.strategy = Some(path),
- }
- }
-}
-
-impl<'a, I: Iterator<Item = &'a syn::Attribute>> From<I> for FieldAttrs {
- fn from(iter: I) -> Self {
+ fn new<'a, I: Iterator<Item = &'a syn::Attribute>>(iter: I) -> Result<Self> {
let mut field_attrs = Self::default();
for attr in iter {
- if !attr.path.is_ident("merge") {
+ if !attr.path().is_ident("merge") {
continue;
}
let parser = syn::punctuated::Punctuated::<FieldAttr, Token![,]>::parse_terminated;
- for attr in attr.parse_args_with(parser).unwrap_or_abort() {
+ for attr in attr.parse_args_with(parser)? {
field_attrs.apply(attr);
}
}
- field_attrs
+ Ok(field_attrs)
+ }
+
+ fn apply(&mut self, attr: FieldAttr) {
+ match attr {
+ FieldAttr::Skip => self.skip = true,
+ FieldAttr::Strategy(path) => self.strategy = Some(path),
+ }
}
}
@@ -144,7 +147,10 @@ impl syn::parse::Parse for FieldAttr {
let path: syn::Path = input.parse()?;
Ok(FieldAttr::Strategy(path))
} else {
- abort!(name, "Unexpected attribute: {}", name)
+ Err(Error::new_spanned(
+ &name,
+ format!("Unexpected attribute: {}", name),
+ ))
}
}
}
|
