scale-borrow

Decode scale in a dynamic way but reasonably efficiently because rust can.

Who this crate is not for

If you are targeting a few specific parachains --> use subxt

If you are targeting lots of parachains and just need something easy --> use scale-value (or https://github.com/virto-network/scales)

Goals

• fun, pleasent
• efficient
• few deps, fast to compile (28 deps)
• wasm compatible - currently using integritee's fork of frame-metadata to achieve this.

How to use

Pic 'n Mix

You can pick and mix the bits you care about into a struct:

   descale! {
      struct MyStruct<'scale> {
            #[path("outer.0.val")]
            named_bool: bool,
            #[path("outer.1.name")]
            named_bool2: &'scale str,
      }
   };
   let my_struct = MyStruct::parse(&encoded[..], top_type_id, &types);

alternatively there's Value.

All the world is a Value

   let val = ValueBuilder::parse(&encoded, top_type_id, &types);
   assert_eq!(
      val,
      Value::Object(Box::new(vec![
         ("_ty", Value::U32(1)),
         ("val", Value::Bool(true)),
         ("name", Value::Str("hi val"))
      ]))
   );

The _ty field is the type of the struct. Tuples and arrays have field names 0, 1, 2 etc.

Status

Very experimental

TODO non-panic error handling,