https://github.com/dreampast/efjson-rust
a streaming JSON parser
https://github.com/dreampast/efjson-rust
json json5 jsonc rust streaming
Last synced: about 2 months ago
JSON representation
a streaming JSON parser
- Host: GitHub
- URL: https://github.com/dreampast/efjson-rust
- Owner: DreamPast
- License: mit
- Created: 2025-05-28T13:23:24.000Z (about 1 year ago)
- Default Branch: master
- Last Pushed: 2025-06-24T14:09:15.000Z (12 months ago)
- Last Synced: 2026-05-01T02:32:49.165Z (about 2 months ago)
- Topics: json, json5, jsonc, rust, streaming
- Language: C++
- Homepage:
- Size: 246 KB
- Stars: 1
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# A Streaming and Event-driven JSON Parser
[English](./README.md) [įŽäŊä¸æ](./README.zh.md)
Other programming languages:
- [Typescript](https://github.com/DreamPast/efjson)
- [C/C++](https://github.com/DreamPast/efjson-cpp)
## Features
- supports JSON5 and JSONC
- stream parser requires minimal memory when no events are triggered
- provides deserialization, which is also streaming
## Example
### Stream Parsing
```rust
use efjson::{stream_parser::StreamParser, ParserOption};
const SRC: &'static str = r#"{
"N":null,"T":true,"F":false,
"str":"str,\"esc\",\uD83D\uDE00,đ",
"num":-1.2e3,"arr":["A",{"obj":"B"}]
}"#;
fn test_stream() {
let tokens = StreamParser::parse(ParserOption::default(), SRC).unwrap();
for item in tokens {
println!("{:?}", item);
}
}
fn main() {
test_stream();
}
```
### Deserialize
```rust
use std::collections::HashMap;
use efjson::{
JsonValue, ParserOption,
deserialize::{JsonRawString, JsonRawToken, deserialize},
};
fn test_deserialize() {
println!("{:?}", deserialize::>(ParserOption::all(), "[1,.1,1.,1.234e3]"));
println!("{:?}", deserialize::>(ParserOption::all(), "[0x1234,0o1234,0b1011]"));
println!("{:?}", deserialize::>(ParserOption::all(), "[Infinity,-Infinity,NaN]"));
println!("{:?}", deserialize::>(ParserOption::all(), "[-0x1234,0o1234,+0b1011]"));
println!(
"{:?}\t{:?}",
deserialize::>(ParserOption::all(), "[true,false]"),
deserialize::<()>(ParserOption::all(), "null")
);
println!(
"{:?}",
deserialize::<[i32; 4]>(ParserOption::all(), "[1,2,3,4]")
);
println!(
"{:?}",
deserialize::>>(ParserOption::all(), "{'a':1,'b':null,}")
);
{
println!("[");
for token in
deserialize::(ParserOption::all(), r#"{'a':12,b:[13,14]}"#).unwrap().tokens
{
println!(" {:?}", token);
}
println!("]");
}
println!(
"{:?}\t",
vec![
deserialize::<(String, i32)>(ParserOption::all(), r#"["a",12]"#),
deserialize::<(String, i32)>(ParserOption::all(), r#"["a",12,]"#),
deserialize::<(String, i32)>(ParserOption::all(), r#"[]"#),
deserialize::<(String, i32)>(ParserOption::all(), r#"["a",]"#),
deserialize::<(String, i32)>(ParserOption::all(), r#"["a",12,13]"#)
]
);
println!(
"{:?}",
deserialize::>(
ParserOption::all(),
r#"{'a':1.2e3,'b':null,'c':"str",'d':[13,14],'e':{a:12,},}"#
)
.unwrap()
.iter()
.map(|(k, v)| (k, &v.json))
.collect::>()
);
println!(
"{:?}",
deserialize::>(
ParserOption::all(),
r#"[1.2e3,null,"str",[13,14,],{a:12,},]"#
)
.unwrap()
.iter_mut()
.map(|x| &x.json)
.collect::>()
);
println!(
"{:?}",
deserialize::(ParserOption::all(), r#"[1.2e3,null,"str",[13,14,],{"a":12,},]"#)
.unwrap()
);
}
fn main() {
test_deserialize();
}
```
And you can use `derive`:
```rust
use std::collections::HashMap;
use efjson::{deserialize::deserialize, Deserializable, ParserOption};
const SRC: &'static str = r#"{
"n":null,"t":true,"f":false,
"str":"str,\"esc\",\uD83D\uDE00,đ",
"num":-1.2e3,"arr":["A",{"obj":"B"}]
}"#;
#[derive(Debug, Deserializable)]
#[allow(dead_code)]
struct Struct {
n: (),
t: bool,
f: bool,
str: String,
num: f64,
arr: (String, HashMap),
}
fn main() {
let r: Result = deserialize(ParserOption::all(), SRC);
println!("{:#?}", r);
}
```
## References
JSON Specification: [RFC 4627 on JSON](https://www.ietf.org/rfc/rfc4627.txt)
JSON State Diagram: [JSON](https://www.json.org/)
JSON5 Specification: [The JSON5 Data Interchange Format](https://spec.json5.org/)
JSON Pointer: [JavaScript Object Notation (JSON) Pointer](https://datatracker.ietf.org/doc/html/rfc6901)
Relative JSON Pointers: [Relative JSON Pointers](https://datatracker.ietf.org/doc/html/draft-bhutton-relative-json-pointer-00)