1// Copyright (c) 2024 Jonas Schäfer <jonas@zombofant.net>
2//
3// This Source Code Form is subject to the terms of the Mozilla Public
4// License, v. 2.0. If a copy of the MPL was not distributed with this
5// file, You can obtain one at http://mozilla.org/MPL/2.0/.
6
7//! Identifiers used within generated code.
8
9use proc_macro2::Span;
10use syn::*;
11
12use crate::types::ref_ty;
13
14/// Container struct for various identifiers used throughout the parser code.
15///
16/// This struct is passed around from the [`crate::compound::Compound`]
17/// downward to the code generators in order to ensure that everyone is on the
18/// same page about which identifiers are used for what.
19///
20/// The recommended usage is to bind the names which are needed into the local
21/// scope like this:
22///
23/// ```text
24/// # let scope = FromEventsScope::new();
25/// let FromEventsScope {
26/// ref attrs,
27/// ..
28/// } = scope;
29/// ```
30pub(crate) struct FromEventsScope {
31 /// Accesses the `AttrMap` from code in
32 /// [`crate::field::FieldBuilderPart::Init`].
33 pub(crate) attrs: Ident,
34
35 /// Accesses the `String` of a `rxml::Event::Text` event from code in
36 /// [`crate::field::FieldBuilderPart::Text`].
37 pub(crate) text: Ident,
38
39 /// Accesses the builder data during parsing.
40 ///
41 /// This should not be used directly outside [`crate::compound`]. Most of
42 /// the time, using [`Self::access_field`] is the correct way to access
43 /// the builder data.
44 pub(crate) builder_data_ident: Ident,
45
46 /// Accesses the result produced by a nested state's builder type.
47 ///
48 /// See [`crate::field::FieldBuilderPart::Nested`].
49 pub(crate) substate_data: Ident,
50
51 /// Accesses the result produced by a nested state's builder type.
52 ///
53 /// See [`crate::field::FieldBuilderPart::Nested`].
54 pub(crate) substate_result: Ident,
55
56 /// Prefix which should be used for any types which are declared, to
57 /// ensure they don't collide with other names.
58 pub(crate) type_prefix: Ident,
59}
60
61impl FromEventsScope {
62 /// Create a fresh scope with all necessary identifiers.
63 pub(crate) fn new(type_prefix: Ident) -> Self {
64 // Sadly, `Ident::new` is not `const`, so we have to create even the
65 // well-known identifiers from scratch all the time.
66 Self {
67 attrs: Ident::new("attrs", Span::call_site()),
68 text: Ident::new("__xso_proc_macro_text_data", Span::call_site()),
69 builder_data_ident: Ident::new("__xso_proc_macro_builder_data", Span::call_site()),
70 substate_data: Ident::new("__xso_proc_macro_substate_data", Span::call_site()),
71 substate_result: Ident::new("__xso_proc_macro_substate_result", Span::call_site()),
72 type_prefix,
73 }
74 }
75
76 /// Generate an expression which accesses the temporary value for the
77 /// given `member` during parsing.
78 pub(crate) fn access_field(&self, member: &Member) -> Expr {
79 Expr::Field(ExprField {
80 attrs: Vec::new(),
81 base: Box::new(Expr::Path(ExprPath {
82 attrs: Vec::new(),
83 qself: None,
84 path: self.builder_data_ident.clone().into(),
85 })),
86 dot_token: syn::token::Dot {
87 spans: [Span::call_site()],
88 },
89 member: Member::Named(mangle_member(member)),
90 })
91 }
92
93 /// Generate an ident with proper scope and span from the type prefix and
94 /// the given member and actual type name.
95 ///
96 /// Due to being merged with the type prefix of this scope and the given
97 /// member, this type name is guaranteed to be unique for unique values of
98 /// `name`.
99 pub(crate) fn make_member_type_name(&self, member: &Member, name: &str) -> Ident {
100 quote::format_ident!(
101 "{}Member{}{}",
102 self.type_prefix,
103 match member {
104 Member::Named(ref ident) => ident.to_string(),
105 Member::Unnamed(Index { index, .. }) => index.to_string(),
106 },
107 name,
108 )
109 }
110}
111
112/// Container struct for various identifiers used throughout the generator
113/// code.
114///
115/// This struct is passed around from the [`crate::compound::Compound`]
116/// downward to the code generators in order to ensure that everyone is on the
117/// same page about which identifiers are used for what.
118///
119/// See [`FromEventsScope`] for recommendations on the usage.
120pub(crate) struct AsItemsScope {
121 /// Lifetime for data borrowed by the implementation.
122 pub(crate) lifetime: Lifetime,
123
124 /// Prefix which should be used for any types which are declared, to
125 /// ensure they don't collide with other names.
126 pub(crate) type_prefix: Ident,
127}
128
129impl AsItemsScope {
130 /// Create a fresh scope with all necessary identifiers.
131 pub(crate) fn new(lifetime: &Lifetime, type_prefix: Ident) -> Self {
132 Self {
133 lifetime: lifetime.clone(),
134 type_prefix,
135 }
136 }
137
138 /// Create a reference to `ty`, borrowed for the lifetime of the AsXml
139 /// impl.
140 pub(crate) fn borrow(&self, ty: Type) -> Type {
141 ref_ty(ty, self.lifetime.clone())
142 }
143
144 /// Generate an ident with proper scope and span from the type prefix and
145 /// the given member and actual type name.
146 ///
147 /// Due to being merged with the type prefix of this scope and the given
148 /// member, this type name is guaranteed to be unique for unique values of
149 /// `name`.
150 pub(crate) fn make_member_type_name(&self, member: &Member, name: &str) -> Ident {
151 quote::format_ident!(
152 "{}Member{}{}",
153 self.type_prefix,
154 match member {
155 Member::Named(ref ident) => ident.to_string(),
156 Member::Unnamed(Index { index, .. }) => index.to_string(),
157 },
158 name,
159 )
160 }
161}
162
163pub(crate) fn mangle_member(member: &Member) -> Ident {
164 match member {
165 Member::Named(member) => quote::format_ident!("f{}", member),
166 Member::Unnamed(member) => quote::format_ident!("f_u{}", member.index),
167 }
168}