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

leo_ast/
lib.rs
