cairo_lang_plugins/plugins/
generate_trait.rs

1use std::iter::zip;
2
3use cairo_lang_defs::patcher::{PatchBuilder, RewriteNode};
4use cairo_lang_defs::plugin::{
5    MacroPlugin, MacroPluginMetadata, PluginDiagnostic, PluginGeneratedFile, PluginResult,
6};
7use cairo_lang_filesystem::ids::SmolStrId;
8use cairo_lang_syntax::attribute::structured::{AttributeArgVariant, AttributeStructurize};
9use cairo_lang_syntax::node::helpers::{BodyItems, GenericParamEx, QueryAttrs};
10use cairo_lang_syntax::node::{Terminal, TypedSyntaxNode, ast};
11use itertools::Itertools;
12use salsa::Database;
13
14#[derive(Debug, Default)]
15#[non_exhaustive]
16pub struct GenerateTraitPlugin;
17
18const GENERATE_TRAIT_ATTR: &str = "generate_trait";
19
20impl MacroPlugin for GenerateTraitPlugin {
21    fn generate_code<'db>(
22        &self,
23        db: &'db dyn Database,
24        item_ast: ast::ModuleItem<'db>,
25        _metadata: &MacroPluginMetadata<'_>,
26    ) -> PluginResult<'db> {
27        match item_ast {
28            ast::ModuleItem::Impl(impl_ast) => generate_trait_for_impl(db, impl_ast),
29            module_item => {
30                let mut diagnostics = vec![];
31
32                if let Some(attr) = module_item.find_attr(db, GENERATE_TRAIT_ATTR) {
33                    diagnostics.push(PluginDiagnostic::warning(
34                        attr.stable_ptr(db),
35                        "`generate_trait` may only be applied to `impl`s".to_string(),
36                    ));
37                }
38
39                PluginResult { diagnostics, ..PluginResult::default() }
40            }
41        }
42    }
43
44    fn declared_attributes<'db>(&self, db: &'db dyn Database) -> Vec<SmolStrId<'db>> {
45        vec![SmolStrId::from(db, GENERATE_TRAIT_ATTR)]
46    }
47}
48
49fn generate_trait_for_impl<'db>(
50    db: &'db dyn Database,
51    impl_ast: ast::ItemImpl<'db>,
52) -> PluginResult<'db> {
53    let Some(attr) = impl_ast.attributes(db).find_attr(db, GENERATE_TRAIT_ATTR) else {
54        return PluginResult::default();
55    };
56    let trait_ast = impl_ast.trait_path(db);
57    let Ok(trait_ast_segment) = trait_ast.segments(db).elements(db).exactly_one() else {
58        return PluginResult {
59            code: None,
60            diagnostics: vec![PluginDiagnostic::error(
61                trait_ast.stable_ptr(db),
62                "Generated trait must have a single element path.".to_string(),
63            )],
64            remove_original_item: false,
65        };
66    };
67
68    let mut diagnostics = vec![];
69    let mut builder = PatchBuilder::new(db, &impl_ast);
70    let leading_trivia = impl_ast
71        .attributes(db)
72        .elements(db)
73        .next()
74        .unwrap()
75        .hash(db)
76        .leading_trivia(db)
77        .as_syntax_node()
78        .get_text(db);
79    let extra_ident = leading_trivia.split('\n').next_back().unwrap_or_default();
80    for attr_arg in attr.structurize(db).args {
81        match attr_arg.variant {
82            AttributeArgVariant::Unnamed(ast::Expr::FunctionCall(attr_arg))
83                if attr_arg.path(db).as_syntax_node().get_text_without_trivia(db).long(db)
84                    == "trait_attrs" =>
85            {
86                for arg in attr_arg.arguments(db).arguments(db).elements(db) {
87                    builder.add_modified(RewriteNode::interpolate_patched(
88                        &format!("{extra_ident}#[$attr$]\n"),
89                        &[("attr".to_string(), RewriteNode::from_ast_trimmed(&arg))].into(),
90                    ));
91                }
92            }
93            _ => {
94                diagnostics.push(PluginDiagnostic::error(
95                    attr_arg.arg.stable_ptr(db),
96                    "Expected an argument with the name `trait_attrs`.".to_string(),
97                ));
98            }
99        }
100    }
101    builder.add_str(extra_ident);
102    builder.add_node(impl_ast.visibility(db).as_syntax_node());
103    builder.add_str("trait ");
104    let impl_generic_params = impl_ast.generic_params(db);
105    let generic_params_match = match trait_ast_segment {
106        ast::PathSegment::WithGenericArgs(segment) => {
107            let generic_args = segment.generic_args(db).generic_args(db);
108            builder.add_node(segment.ident(db).as_syntax_node());
109            if let ast::OptionWrappedGenericParamList::WrappedGenericParamList(
110                impl_generic_params,
111            ) = impl_generic_params.clone()
112            {
113                // TODO(orizi): Support generic args that do not directly match the generic params.
114                let trait_generic_args = generic_args.elements(db);
115                let longer_lived = impl_generic_params.generic_params(db);
116                let impl_generic_params = longer_lived.elements(db);
117                zip(trait_generic_args, impl_generic_params).all(
118                    |(trait_generic_arg, impl_generic_param)| {
119                        let ast::GenericArg::Unnamed(trait_generic_arg) = trait_generic_arg else {
120                            return false;
121                        };
122                        let ast::Expr::Path(trait_generic_arg) = trait_generic_arg.value(db) else {
123                            return false;
124                        };
125                        let Ok(ast::PathSegment::Simple(trait_generic_arg)) =
126                            trait_generic_arg.segments(db).elements(db).exactly_one()
127                        else {
128                            return false;
129                        };
130                        let trait_generic_arg_name = trait_generic_arg.ident(db);
131                        let Some(impl_generic_param_name) = impl_generic_param.name(db) else {
132                            return false;
133                        };
134                        trait_generic_arg_name.text(db) == impl_generic_param_name.text(db)
135                    },
136                )
137            } else {
138                false
139            }
140        }
141        ast::PathSegment::Simple(segment) => {
142            builder.add_node(segment.ident(db).as_syntax_node());
143            matches!(impl_generic_params, ast::OptionWrappedGenericParamList::Empty(_))
144        }
145        ast::PathSegment::Missing(_) => {
146            return PluginResult {
147                code: None,
148                diagnostics: vec![PluginDiagnostic::error(
149                    trait_ast.stable_ptr(db),
150                    "Generated trait cannot have a missing path segment.".to_string(),
151                )],
152                remove_original_item: false,
153            };
154        }
155    };
156    if !generic_params_match {
157        diagnostics.push(PluginDiagnostic::error(
158            trait_ast.stable_ptr(db),
159            "Generated trait must have generic args matching the impl's generic params."
160                .to_string(),
161        ));
162    }
163    match impl_ast.body(db) {
164        ast::MaybeImplBody::None(semicolon) => {
165            builder.add_modified(RewriteNode::from_ast_trimmed(&impl_generic_params));
166            builder.add_node(semicolon.as_syntax_node());
167        }
168        ast::MaybeImplBody::Some(body) => {
169            builder.add_node(impl_generic_params.as_syntax_node());
170            builder.add_node(body.lbrace(db).as_syntax_node());
171            for item in body.iter_items(db) {
172                match item {
173                    ast::ImplItem::Function(function_item) => {
174                        let decl = function_item.declaration(db);
175                        let signature = decl.signature(db);
176                        builder.add_node(function_item.attributes(db).as_syntax_node());
177                        builder.add_node(decl.optional_const(db).as_syntax_node());
178                        builder.add_node(decl.function_kw(db).as_syntax_node());
179                        builder.add_node(decl.name(db).as_syntax_node());
180                        builder.add_node(decl.generic_params(db).as_syntax_node());
181                        builder.add_node(signature.lparen(db).as_syntax_node());
182                        for node in signature.parameters(db).node.get_children(db).iter() {
183                            if let Some(param) = ast::Param::cast(db, *node) {
184                                for modifier in param.modifiers(db).elements(db) {
185                                    // `mut` modifiers are only relevant for impls, not traits.
186                                    if !matches!(modifier, ast::Modifier::Mut(_)) {
187                                        builder.add_node(modifier.as_syntax_node());
188                                    }
189                                }
190                                builder.add_node(param.name(db).as_syntax_node());
191                                builder.add_node(param.type_clause(db).as_syntax_node());
192                            } else {
193                                builder.add_node(*node);
194                            }
195                        }
196                        let rparen = signature.rparen(db);
197                        let ret_ty = signature.ret_ty(db);
198                        let implicits_clause = signature.implicits_clause(db);
199                        let optional_no_panic = signature.optional_no_panic(db);
200                        let last_node = if matches!(
201                            optional_no_panic,
202                            ast::OptionTerminalNoPanic::TerminalNoPanic(_)
203                        ) {
204                            builder.add_node(rparen.as_syntax_node());
205                            builder.add_node(ret_ty.as_syntax_node());
206                            builder.add_node(implicits_clause.as_syntax_node());
207                            optional_no_panic.as_syntax_node()
208                        } else if matches!(
209                            implicits_clause,
210                            ast::OptionImplicitsClause::ImplicitsClause(_)
211                        ) {
212                            builder.add_node(rparen.as_syntax_node());
213                            builder.add_node(ret_ty.as_syntax_node());
214                            implicits_clause.as_syntax_node()
215                        } else if matches!(ret_ty, ast::OptionReturnTypeClause::ReturnTypeClause(_))
216                        {
217                            builder.add_node(rparen.as_syntax_node());
218                            ret_ty.as_syntax_node()
219                        } else {
220                            rparen.as_syntax_node()
221                        };
222                        builder.add_modified(RewriteNode::Trimmed {
223                            node: last_node,
224                            trim_left: false,
225                            trim_right: true,
226                        });
227                        builder.add_str(";\n");
228                    }
229                    ast::ImplItem::Type(type_item) => {
230                        builder.add_node(type_item.attributes(db).as_syntax_node());
231                        builder.add_node(type_item.type_kw(db).as_syntax_node());
232                        builder.add_modified(RewriteNode::Trimmed {
233                            node: type_item.name(db).as_syntax_node(),
234                            trim_left: false,
235                            trim_right: true,
236                        });
237                        builder.add_str(";\n");
238                    }
239                    ast::ImplItem::Constant(const_item) => {
240                        builder.add_node(const_item.attributes(db).as_syntax_node());
241                        builder.add_node(const_item.const_kw(db).as_syntax_node());
242                        builder.add_node(const_item.name(db).as_syntax_node());
243                        builder.add_modified(RewriteNode::Trimmed {
244                            node: const_item.type_clause(db).as_syntax_node(),
245                            trim_left: false,
246                            trim_right: true,
247                        });
248                        builder.add_str(";\n");
249                    }
250                    _ => diagnostics.push(PluginDiagnostic::error(
251                        item.stable_ptr(db),
252                        "Only functions, types, and constants are supported in #[generate_trait]."
253                            .to_string(),
254                    )),
255                }
256            }
257            builder.add_node(body.rbrace(db).as_syntax_node());
258        }
259    }
260    let (content, code_mappings) = builder.build();
261    PluginResult {
262        code: Some(PluginGeneratedFile {
263            name: "generate_trait".into(),
264            content,
265            code_mappings,
266            aux_data: None,
267            diagnostics_note: Default::default(),
268            is_unhygienic: false,
269        }),
270        diagnostics,
271        remove_original_item: false,
272    }
273}
cairo_lang_plugins/plugins/generate_trait.rs

cairo_lang_plugins/plugins/
generate_trait.rs
