leo_ast/
lib.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//! The abstract syntax tree (ast) for a Leo program.
18//!
19//! This module contains the [`Ast`] type, a wrapper around the [`Program`] type.
20//! The [`Ast`] type is intended to be parsed and modified by different passes
21//! of the Leo compiler. The Leo compiler can generate a set of R1CS constraints from any [`Ast`].
22
23#![allow(ambiguous_glob_reexports)]
24
25mod r#struct;
26pub use self::r#struct::*;
27
28pub mod common;
29pub use self::common::*;
30
31pub mod constructor;
32pub use self::constructor::*;
33
34mod expressions;
35pub use self::expressions::*;
36
37mod functions;
38pub use self::functions::*;
39
40mod indent_display;
41use indent_display::*;
42
43pub mod interpreter_value;
44
45mod mapping;
46pub use self::mapping::*;
47
48mod module;
49pub use self::module::*;
50
51mod passes;
52pub use self::passes::*;
53
54mod program;
55pub use self::program::*;
56
57mod statement;
58pub use self::statement::*;
59
60mod storage;
61pub use self::storage::*;
62
63mod types;
64pub use self::types::*;
65
66mod stub;
67pub use self::stub::*;
68
69pub use common::node::*;
70
71use leo_errors::{AstError, Result};
72
73/// The abstract syntax tree (AST) for a Leo program.
74///
75/// The [`Ast`] type represents a Leo program as a series of recursive data types.
76/// These data types form a tree that begins from a [`Program`] type root.
77#[derive(Clone, Debug, Default, Eq, PartialEq)]
78pub struct Ast {
79    pub ast: Program,
80}
81
82impl Ast {
83    /// Creates a new AST from a given program tree.
84    pub fn new(program: Program) -> Self {
85        Self { ast: program }
86    }
87
88    /// Returns a reference to the inner program AST representation.
89    pub fn as_repr(&self) -> &Program {
90        &self.ast
91    }
92
93    pub fn into_repr(self) -> Program {
94        self.ast
95    }
96
97    /// Serializes the ast into a JSON string.
98    pub fn to_json_string(&self) -> Result<String> {
99        Ok(serde_json::to_string_pretty(&self.ast).map_err(|e| AstError::failed_to_convert_ast_to_json_string(&e))?)
100    }
101
102    // Converts the ast into a JSON value.
103    // Note that there is no corresponding `from_json_value` function
104    // since we modify JSON values leaving them unable to be converted
105    // back into Programs.
106    pub fn to_json_value(&self) -> Result<serde_json::Value> {
107        Ok(serde_json::to_value(&self.ast).map_err(|e| AstError::failed_to_convert_ast_to_json_value(&e))?)
108    }
109
110    /// Serializes the ast into a JSON file.
111    pub fn to_json_file(&self, mut path: std::path::PathBuf, file_name: &str) -> Result<()> {
112        path.push(file_name);
113        let file = std::fs::File::create(&path).map_err(|e| AstError::failed_to_create_ast_json_file(&path, &e))?;
114        let writer = std::io::BufWriter::new(file);
115        Ok(serde_json::to_writer_pretty(writer, &self.ast)
116            .map_err(|e| AstError::failed_to_write_ast_to_json_file(&path, &e))?)
117    }
118
119    /// Serializes the ast into a JSON value and removes keys from object mappings before writing to a file.
120    pub fn to_json_file_without_keys(
121        &self,
122        mut path: std::path::PathBuf,
123        file_name: &str,
124        excluded_keys: &[&str],
125    ) -> Result<()> {
126        path.push(file_name);
127        let file = std::fs::File::create(&path).map_err(|e| AstError::failed_to_create_ast_json_file(&path, &e))?;
128        let writer = std::io::BufWriter::new(file);
129
130        let mut value = self.to_json_value().unwrap();
131        for key in excluded_keys {
132            value = remove_key_from_json(value, key);
133        }
134        value = normalize_json_value(value);
135
136        Ok(serde_json::to_writer_pretty(writer, &value)
137            .map_err(|e| AstError::failed_to_write_ast_to_json_file(&path, &e))?)
138    }
139
140    /// Deserializes the JSON string into a ast.
141    pub fn from_json_string(json: &str) -> Result<Self> {
142        let ast: Program = serde_json::from_str(json).map_err(|e| AstError::failed_to_read_json_string_to_ast(&e))?;
143        Ok(Self { ast })
144    }
145
146    /// Deserializes the JSON string into a ast from a file.
147    pub fn from_json_file(path: std::path::PathBuf) -> Result<Self> {
148        let data = std::fs::read_to_string(&path).map_err(|e| AstError::failed_to_read_json_file(&path, &e))?;
149        Self::from_json_string(&data)
150    }
151}
152
153impl AsRef<Program> for Ast {
154    fn as_ref(&self) -> &Program {
155        &self.ast
156    }
157}
158
159/// Helper function to recursively filter keys from AST JSON
160pub fn remove_key_from_json(value: serde_json::Value, key: &str) -> serde_json::Value {
161    match value {
162        serde_json::Value::Object(map) => serde_json::Value::Object(
163            map.into_iter().filter(|(k, _)| k != key).map(|(k, v)| (k, remove_key_from_json(v, key))).collect(),
164        ),
165        serde_json::Value::Array(values) => {
166            serde_json::Value::Array(values.into_iter().map(|v| remove_key_from_json(v, key)).collect())
167        }
168        _ => value,
169    }
170}
171
172/// Helper function to normalize AST JSON into a form compatible with tgc.
173/// This function will traverse the original JSON value and produce a new
174/// one under the following rules:
175/// 1. Remove empty object mappings from JSON arrays
176/// 2. If there are two elements in a JSON array and one is an empty object
177///    mapping and the other is not, then lift up the one that isn't
178pub fn normalize_json_value(value: serde_json::Value) -> serde_json::Value {
179    match value {
180        serde_json::Value::Array(vec) => {
181            let orig_length = vec.len();
182            let mut new_vec: Vec<serde_json::Value> = vec
183                .into_iter()
184                .filter(|v| !matches!(v, serde_json::Value::Object(map) if map.is_empty()))
185                .map(normalize_json_value)
186                .collect();
187
188            if orig_length == 2 && new_vec.len() == 1 {
189                new_vec.pop().unwrap()
190            } else {
191                serde_json::Value::Array(new_vec)
192            }
193        }
194        serde_json::Value::Object(map) => {
195            serde_json::Value::Object(map.into_iter().map(|(k, v)| (k, normalize_json_value(v))).collect())
196        }
197        _ => value,
198    }
199}
leo_ast/lib.rs

leo_ast/
lib.rs
