Type System

Primitive types

Type	Size	Description
`i64`	8 bytes	64-bit signed integer
`f64`	8 bytes	64-bit IEEE 754 float
`bool`	1 byte	Boolean (i8 in Cranelift)
`void`	0 bytes	No value (unit type)

Heap types

Type	Description
`string`	UTF-8 string (runtime-managed)
`array<T>`	Dynamic array of type T
`struct<Name>`	Named struct with typed fields

Reference types

Type	Description
`&T`	Immutable reference
`&mut T`	Mutable reference (exclusive)

Error handling types

Type	Description
`result<T, E>`	Success (`Ok(T)`) or failure (`Err(E)`)
`option<T>`	Value (`Some(T)`) or nothing (`None`)

Type annotations in JSON-LD

Types are specified via duumbi:valueType and duumbi:returnType:

{
  "@type": "duumbi:Const",
  "duumbi:value": 42,
  "duumbi:valueType": "i64"
}

{
  "@type": "duumbi:Function",
  "duumbi:returnType": "result<i64, string>",
  "duumbi:params": [
    { "duumbi:name": "x", "duumbi:paramType": "&array<i64>" }
  ]
}

Type compatibility

Arithmetic ops (Add, Sub, Mul, Div) require matching operand types
Compare works on matching numeric types, returning bool
Branch requires a bool condition
Call validates parameter types against function signature
Match requires a result<T,E> or option<T> discriminant