Newer
Older
Louis
committed
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
use crate::fqpath::*;
use crate::utils::{ident_prefix, ident_suffix, snake_case_ident};
use proc_macro2::{Ident, TokenStream};
use quote::{quote, quote_spanned, ToTokens};
use syn::{
parse_quote, spanned::Spanned, Attribute, Data, DataEnum, DataStruct, DeriveInput, Field, Meta,
Variant, Visibility,
};
macro_rules! err_message {
($spannable: expr, $($tok:tt)*) => {
return quote_spanned!(
$spannable.span() =>
compile_error!($($tok)*);
)
};
}
pub fn event_system(DeriveInput { data, ident, .. }: DeriveInput) -> TokenStream {
let enum_data = match data {
Data::Struct(d) => err_message!(
d.struct_token,
"Can't create an event system from an enum type"
),
Data::Enum(data_enum) => data_enum,
Data::Union(u) => err_message!(
u.union_token,
"Can't create an asset system from a union type"
),
};
let structs = define_structs(&enum_data);
let root = define_root_enum(&ident, &enum_data);
let helper = define_helper_fn(&ident, &enum_data);
let plugin = define_plugin(&ident, &enum_data);
quote! {
#structs
#root
#helper
#plugin
}
}
fn define_structs(data: &DataEnum) -> TokenStream {
data.variants
.iter()
.map(
|Variant {
ident,
attrs,
fields,
..
}| {
let event_name = ident_suffix(ident, "Event");
let fields: TokenStream = fields
.iter()
.map(|fl @ Field { ident, ty, .. }| {
let f = Field {
ident: ident.clone(),
ty: ty.clone(),
vis: parse_quote!(pub),
..fl.clone()
}
.to_token_stream();
Louis
committed
Louis
committed
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
.collect();
quote! {
#[derive(#FQClone, #FQDebug, #BevyEvent, #FQSerialize, #FQDeserialize)]
pub struct #event_name {
#fields
}
}
},
)
.collect()
}
fn define_root_enum(name: &Ident, data: &DataEnum) -> TokenStream {
let variants: TokenStream = data
.variants
.iter()
.map(|Variant { ident, .. }| {
let event = ident_suffix(ident, "Event");
quote!(#ident(#event),)
})
.collect();
let conversions: TokenStream = data
.variants
.iter()
.map(|Variant { ident, .. }| {
let event = ident_suffix(ident, "Event");
quote! {
impl #FQFrom<#event> for #name {
fn from(value: #event) -> Self {
#name::#ident(value)
}
}
}
})
.collect();
quote! {
#[derive(#FQDebug, #FQClone, #BevyEvent, #FQSerialize, #FQDeserialize)]
pub enum #name {
#variants
}
#conversions
}
}
fn define_helper_fn(name: &Ident, data: &DataEnum) -> TokenStream {
let variants: TokenStream = data
.variants
.iter()
.map(|Variant { ident, .. }| quote! { #name::#ident(value) => #send_event(world, value), })
.collect();
let fn_name = ident_prefix(&snake_case_ident(name), "dispatch_");
quote! {
pub fn #fn_name(world: &mut #BevyWorld, event: #name) {
match event {
#variants
}
}
}
}
fn define_plugin(name: &Ident, data: &DataEnum) -> TokenStream {
let variants: TokenStream = data
.variants
.iter()
.map(|Variant { ident, .. }| {
let event = ident_suffix(ident, "Event");
quote!(app.add_event::<#event>();)
})
.collect();
let plugin_name = ident_suffix(name, "Plugin");
quote! {
pub struct #plugin_name;
impl #BevyPlugin for #plugin_name {
fn build(&self, app: &mut #BevyApp) {
#variants
}
}
}
}