SML

SML is a simple markup language. It is designed to convert human readable information into Rust data-structures.

The format looks this,

text hobbit: name: "Frodo Baggins" age: "98" friends: hobbit: name: "Bilbo Baggins" age: "176" hobbit: name: "Samwise Gamgee" age: "66"

Data Format Rules

1. Indentation has meaning and is 4 spaces, relative to the top key.

2. All values must be double quoted.

3. Every key/value combination must be nested in a key. For example hobbit: "Frodo" by itself is invalid. It can be written: hobbit: name: "Frodo" The motivation behind this is for the data format to distinguish clearly between whole data structures, which are headed by a key only, and parts of a data structure which are either key/value pairs, representing fields or variants, or other data-structures, which again are headed by a key only.

4. Separation of lines has meaning.

5. Keys may not include :.

6. Double quotes in values must be escaped using \".

7. Everything after the second double quote is ignored (and can be used for commenting).

8. Empty lines or lines with whitespace only are ignored.

Basic Organization

text ToSmall trait to_string() ---> ---> ------------- ----------- ---------- | data- | | Small | | String | | structure | | | | | ------------- ----------- ---------- <--- <--- FromSmall from_str() trait

Example

To convert from Small to a data-structure,

```rust use small::{Small, FromSmall, SmallError};

[derive(Debug)]

struct Hobbit { name: String, age: u32, friends: Vec, bicycle: Option, }

impl Small for Hobbit { fn from_small(small: Small) -> Result { Ok(Self { name: String::sml(&small, "hobbit::name")?, age: u32::sml(&small, "hobbit::age")?, friends: Vec::::sml(&small, "hobbit::friends::hobbit")?, bicycle: Option::::sml(&small, "hobbit::bicycle")?, }) } }

fn main() { let s = r#" hobbit: name: "Frodo Baggins" age: "98" friends: hobbit: name: "Bilbo Baggins" age: "176" hobbit: name: "Samwise Gamgee" age: "66""#;

let frodo = Hobbit::from_str_debug(s);

}

```

and to convert from a data-structure to Small,

```rust use sml::{Small, ToSmall, SmallError};

[derive(Debug)]

struct Hobbit { name: String, age: u32, friends: Vec, bicycle: Option, }

impl ToSmall for Hobbit { fn tosmall(&self, key: &str) -> Result { Small::join(key, &vec!( self.name.tosmall("name")?,
self.age.tosmall("age")?,
self.friends.tosmall("friends")?,
self.bicycle.to_small("bicycle")?, )) } }

println!("{}", frodo::to_small("hobbit"));

// hobbit: // name: "Frodo Baggins" // age: "98" // friends: // hobbit: // name: "Bilbo Baggins" // age: "176" // hobbit: // name: "Samwise Gamgee" // age: "66" ```