leo_ast/passes/
visitor.rs

1// Copyright (C) 2019-2025 Provable Inc.
2// This file is part of the Leo library.
3
4// The Leo library is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8
9// The Leo library is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12// GNU General Public License for more details.
13
14// You should have received a copy of the GNU General Public License
15// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
16
17//! This module contains Visitor trait implementations for the AST.
18//! It implements default methods for each node to be made
19//! given the type of node its visiting.
20
21use crate::*;
22
23// TODO: The Visitor and Reconstructor patterns need a redesign so that the default implementation can easily be invoked though its implemented in an overriding trait.
24// Here is a pattern that seems to work
25// trait ProgramVisitor {
26//     // The trait method that can be overridden
27//     fn visit_program_scope(&mut self);
28//
29//     // Private helper function containing the default implementation
30//     fn default_visit_program_scope(&mut self) {
31//         println!("Do default stuff");
32//     }
33// }
34//
35// struct YourStruct;
36//
37// impl ProgramVisitor for YourStruct {
38//     fn visit_program_scope(&mut self) {
39//         println!("Do custom stuff.");
40//         // Call the default implementation
41//         self.default_visit_program_scope();
42//     }
43// }
44
45/// A Visitor trait for types in the AST.
46pub trait TypeVisitor: ExpressionVisitor {
47    fn visit_type(&mut self, input: &Type) {
48        match input {
49            Type::Array(array_type) => self.visit_array_type(array_type),
50            Type::Future(future_type) => self.visit_future_type(future_type),
51            Type::Mapping(mapping_type) => self.visit_mapping_type(mapping_type),
52            Type::Tuple(tuple_type) => self.visit_tuple_type(tuple_type),
53            Type::Address
54            | Type::Boolean
55            | Type::Composite(_)
56            | Type::Field
57            | Type::Group
58            | Type::Identifier(_)
59            | Type::Integer(_)
60            | Type::Scalar
61            | Type::Signature
62            | Type::String
63            | Type::Numeric
64            | Type::Unit
65            | Type::Err => {}
66        }
67    }
68
69    fn visit_array_type(&mut self, input: &ArrayType) {
70        self.visit_type(&input.element_type);
71        self.visit_expression(&input.length, &Default::default());
72    }
73
74    fn visit_future_type(&mut self, input: &FutureType) {
75        input.inputs.iter().for_each(|input| self.visit_type(input));
76    }
77
78    fn visit_mapping_type(&mut self, input: &MappingType) {
79        self.visit_type(&input.key);
80        self.visit_type(&input.value);
81    }
82
83    fn visit_tuple_type(&mut self, input: &TupleType) {
84        input.elements().iter().for_each(|input| self.visit_type(input));
85    }
86}
87
88/// A Visitor trait for expressions in the AST.
89pub trait ExpressionVisitor {
90    type AdditionalInput: Default;
91    type Output: Default;
92
93    fn visit_expression(&mut self, input: &Expression, additional: &Self::AdditionalInput) -> Self::Output {
94        match input {
95            Expression::Array(array) => self.visit_array(array, additional),
96            Expression::ArrayAccess(access) => self.visit_array_access(access, additional),
97            Expression::AssociatedConstant(constant) => self.visit_associated_constant(constant, additional),
98            Expression::AssociatedFunction(function) => self.visit_associated_function(function, additional),
99            Expression::Binary(binary) => self.visit_binary(binary, additional),
100            Expression::Call(call) => self.visit_call(call, additional),
101            Expression::Cast(cast) => self.visit_cast(cast, additional),
102            Expression::Struct(struct_) => self.visit_struct_init(struct_, additional),
103            Expression::Err(err) => self.visit_err(err, additional),
104            Expression::Identifier(identifier) => self.visit_identifier(identifier, additional),
105            Expression::Literal(literal) => self.visit_literal(literal, additional),
106            Expression::Locator(locator) => self.visit_locator(locator, additional),
107            Expression::MemberAccess(access) => self.visit_member_access(access, additional),
108            Expression::Repeat(repeat) => self.visit_repeat(repeat, additional),
109            Expression::Ternary(ternary) => self.visit_ternary(ternary, additional),
110            Expression::Tuple(tuple) => self.visit_tuple(tuple, additional),
111            Expression::TupleAccess(access) => self.visit_tuple_access(access, additional),
112            Expression::Unary(unary) => self.visit_unary(unary, additional),
113            Expression::Unit(unit) => self.visit_unit(unit, additional),
114        }
115    }
116
117    fn visit_array_access(&mut self, input: &ArrayAccess, additional: &Self::AdditionalInput) -> Self::Output {
118        self.visit_expression(&input.array, additional);
119        self.visit_expression(&input.index, additional);
120        Default::default()
121    }
122
123    fn visit_member_access(&mut self, input: &MemberAccess, additional: &Self::AdditionalInput) -> Self::Output {
124        self.visit_expression(&input.inner, additional);
125        Default::default()
126    }
127
128    fn visit_tuple_access(&mut self, input: &TupleAccess, additional: &Self::AdditionalInput) -> Self::Output {
129        self.visit_expression(&input.tuple, additional);
130        Default::default()
131    }
132
133    fn visit_array(&mut self, input: &ArrayExpression, additional: &Self::AdditionalInput) -> Self::Output {
134        input.elements.iter().for_each(|expr| {
135            self.visit_expression(expr, additional);
136        });
137        Default::default()
138    }
139
140    fn visit_associated_constant(
141        &mut self,
142        _input: &AssociatedConstantExpression,
143        _additional: &Self::AdditionalInput,
144    ) -> Self::Output {
145        Default::default()
146    }
147
148    fn visit_associated_function(
149        &mut self,
150        input: &AssociatedFunctionExpression,
151        _additional: &Self::AdditionalInput,
152    ) -> Self::Output {
153        input.arguments.iter().for_each(|arg| {
154            self.visit_expression(arg, &Default::default());
155        });
156        Default::default()
157    }
158
159    fn visit_binary(&mut self, input: &BinaryExpression, additional: &Self::AdditionalInput) -> Self::Output {
160        self.visit_expression(&input.left, additional);
161        self.visit_expression(&input.right, additional);
162        Default::default()
163    }
164
165    fn visit_call(&mut self, input: &CallExpression, additional: &Self::AdditionalInput) -> Self::Output {
166        input.arguments.iter().for_each(|expr| {
167            self.visit_expression(expr, additional);
168        });
169        Default::default()
170    }
171
172    fn visit_cast(&mut self, input: &CastExpression, additional: &Self::AdditionalInput) -> Self::Output {
173        self.visit_expression(&input.expression, additional);
174        Default::default()
175    }
176
177    fn visit_struct_init(&mut self, input: &StructExpression, additional: &Self::AdditionalInput) -> Self::Output {
178        for StructVariableInitializer { expression, .. } in input.members.iter() {
179            if let Some(expression) = expression {
180                self.visit_expression(expression, additional);
181            }
182        }
183        Default::default()
184    }
185
186    fn visit_err(&mut self, _input: &ErrExpression, _additional: &Self::AdditionalInput) -> Self::Output {
187        panic!("`ErrExpression`s should not be in the AST at this phase of compilation.")
188    }
189
190    fn visit_identifier(&mut self, _input: &Identifier, _additional: &Self::AdditionalInput) -> Self::Output {
191        Default::default()
192    }
193
194    fn visit_literal(&mut self, _input: &Literal, _additional: &Self::AdditionalInput) -> Self::Output {
195        Default::default()
196    }
197
198    fn visit_locator(&mut self, _input: &LocatorExpression, _additional: &Self::AdditionalInput) -> Self::Output {
199        Default::default()
200    }
201
202    fn visit_repeat(&mut self, input: &RepeatExpression, additional: &Self::AdditionalInput) -> Self::Output {
203        self.visit_expression(&input.expr, additional);
204        self.visit_expression(&input.count, additional);
205        Default::default()
206    }
207
208    fn visit_ternary(&mut self, input: &TernaryExpression, additional: &Self::AdditionalInput) -> Self::Output {
209        self.visit_expression(&input.condition, additional);
210        self.visit_expression(&input.if_true, additional);
211        self.visit_expression(&input.if_false, additional);
212        Default::default()
213    }
214
215    fn visit_tuple(&mut self, input: &TupleExpression, additional: &Self::AdditionalInput) -> Self::Output {
216        input.elements.iter().for_each(|expr| {
217            self.visit_expression(expr, additional);
218        });
219        Default::default()
220    }
221
222    fn visit_unary(&mut self, input: &UnaryExpression, additional: &Self::AdditionalInput) -> Self::Output {
223        self.visit_expression(&input.receiver, additional);
224        Default::default()
225    }
226
227    fn visit_unit(&mut self, _input: &UnitExpression, _additional: &Self::AdditionalInput) -> Self::Output {
228        Default::default()
229    }
230}
231
232/// A Visitor trait for statements in the AST.
233pub trait StatementVisitor: TypeVisitor {
234    fn visit_statement(&mut self, input: &Statement) {
235        match input {
236            Statement::Assert(stmt) => self.visit_assert(stmt),
237            Statement::Assign(stmt) => self.visit_assign(stmt),
238            Statement::Block(stmt) => self.visit_block(stmt),
239            Statement::Conditional(stmt) => self.visit_conditional(stmt),
240            Statement::Const(stmt) => self.visit_const(stmt),
241            Statement::Definition(stmt) => self.visit_definition(stmt),
242            Statement::Expression(stmt) => self.visit_expression_statement(stmt),
243            Statement::Iteration(stmt) => self.visit_iteration(stmt),
244            Statement::Return(stmt) => self.visit_return(stmt),
245        }
246    }
247
248    fn visit_assert(&mut self, input: &AssertStatement) {
249        match &input.variant {
250            AssertVariant::Assert(expr) => self.visit_expression(expr, &Default::default()),
251            AssertVariant::AssertEq(left, right) | AssertVariant::AssertNeq(left, right) => {
252                self.visit_expression(left, &Default::default());
253                self.visit_expression(right, &Default::default())
254            }
255        };
256    }
257
258    fn visit_assign(&mut self, input: &AssignStatement) {
259        self.visit_expression(&input.value, &Default::default());
260    }
261
262    fn visit_block(&mut self, input: &Block) {
263        input.statements.iter().for_each(|stmt| self.visit_statement(stmt));
264    }
265
266    fn visit_conditional(&mut self, input: &ConditionalStatement) {
267        self.visit_expression(&input.condition, &Default::default());
268        self.visit_block(&input.then);
269        if let Some(stmt) = input.otherwise.as_ref() {
270            self.visit_statement(stmt);
271        }
272    }
273
274    fn visit_const(&mut self, input: &ConstDeclaration) {
275        self.visit_type(&input.type_);
276        self.visit_expression(&input.value, &Default::default());
277    }
278
279    fn visit_definition(&mut self, input: &DefinitionStatement) {
280        if let Some(ty) = input.type_.as_ref() {
281            self.visit_type(ty)
282        }
283        self.visit_expression(&input.value, &Default::default());
284    }
285
286    fn visit_expression_statement(&mut self, input: &ExpressionStatement) {
287        self.visit_expression(&input.expression, &Default::default());
288    }
289
290    fn visit_iteration(&mut self, input: &IterationStatement) {
291        if let Some(ty) = input.type_.as_ref() {
292            self.visit_type(ty)
293        }
294        self.visit_expression(&input.start, &Default::default());
295        self.visit_expression(&input.stop, &Default::default());
296        self.visit_block(&input.block);
297    }
298
299    fn visit_return(&mut self, input: &ReturnStatement) {
300        self.visit_expression(&input.expression, &Default::default());
301    }
302}
303
304/// A Visitor trait for the program represented by the AST.
305pub trait ProgramVisitor: StatementVisitor {
306    fn visit_program(&mut self, input: &Program) {
307        input.imports.values().for_each(|import| self.visit_import(&import.0));
308        input.stubs.values().for_each(|stub| self.visit_stub(stub));
309        input.program_scopes.values().for_each(|scope| self.visit_program_scope(scope));
310    }
311
312    fn visit_program_scope(&mut self, input: &ProgramScope) {
313        input.structs.iter().for_each(|(_, c)| (self.visit_struct(c)));
314
315        input.mappings.iter().for_each(|(_, c)| (self.visit_mapping(c)));
316
317        input.functions.iter().for_each(|(_, c)| (self.visit_function(c)));
318
319        input.consts.iter().for_each(|(_, c)| (self.visit_const(c)));
320    }
321
322    fn visit_stub(&mut self, _input: &Stub) {}
323
324    fn visit_import(&mut self, input: &Program) {
325        self.visit_program(input)
326    }
327
328    fn visit_struct(&mut self, input: &Composite) {
329        input.members.iter().for_each(|member| self.visit_type(&member.type_));
330    }
331
332    fn visit_mapping(&mut self, input: &Mapping) {
333        self.visit_type(&input.key_type);
334        self.visit_type(&input.value_type);
335    }
336
337    fn visit_function(&mut self, input: &Function) {
338        input.const_parameters.iter().for_each(|input| self.visit_type(&input.type_));
339        input.input.iter().for_each(|input| self.visit_type(&input.type_));
340        input.output.iter().for_each(|output| self.visit_type(&output.type_));
341        self.visit_type(&input.output_type);
342        self.visit_block(&input.block);
343    }
344
345    fn visit_function_stub(&mut self, _input: &FunctionStub) {}
346
347    fn visit_struct_stub(&mut self, _input: &Composite) {}
348}
leo_ast/passes/visitor.rs

leo_ast/passes/
visitor.rs
