deser_hjson

This is a Serde 1.0 compatible deserializer for Hjson, tailored for derive powered deserialization.

It's a work-in-progress, having been tested only minimally for now.

If you're interested in using this deserializer, or notice a problem, please come and tell me on Miaou.

Example

This Hjson document comes from Hjson's introduction

```rust use { deser_hjson::, serde::Deserialize, std::collections::HashMap, }; let hjson = r#" { // use #, // or /*/ comments, // omit quotes for keys key: 1 // omit quotes for strings contains: everything on this line // omit commas at the end of a line cool: { foo: 1 bar: 2 } // allow trailing commas list: [ 1, 2, ] // and use multiline strings realist: ''' My half empty glass, I will fill your empty half. Now you are half full. ''' } "#; // we'll deserialize it into this struct:

[derive(Deserialize, PartialEq, Debug)]

struct Example { key: i32, contains: Option, cool: HashMap, list: Vec, realist: String, missing: Option, } let mut cool = HashMap::new(); cool.insert("foo".toowned(), 1); cool.insert("bar".toowned(), 2); let expected = Example { key: 1, contains: Some("everything on this line".toowned()), cool, list: vec![1, 2], realist: "My half empty glass,\nI will fill your empty half.\nNow you are half full.".toowned(), missing: None, }; // Here's the deserialization and the equality check: asserteq!(expected, fromstr(hjson).unwrap()); ```

Limits

Colons in quoteless strings

Quoteless strings in Hjson end with the line and can contain colons. But serde doesn't know, when reading, if a string is logically a "value" or a "key" in a map. It means that if we allow colons in quoteles strings the following Hjson

{
    key: value
}

would be correctly interpreted when deserialized into a struct (because key is then known as an identifier) but wouldn't be correctly deserialized into HashMap<String, String>.

It seems to me the less surprising choice is to not allow colons in quoteless strings (they're hard to parse for an human too anyway) until I find how to reliably parse quoteless map keys with Serde 1.0.