Cairo type hints

Add type hints to your Cairo-lang files and feed the generated json files to Stark-Dot-Net code generators.

Install

pip install cairo-type-hints

Example usage:

python compile-cairo-type-hints \
    -i ./src/my-awesome-contract.cairo \
    -o ./artifacts/hints/test-hints.json

Adding hints to structs

A type hint is a comment with a colon, a space and then a type. Valid types are int, string, and address. For example, #: int.

Type hints are added inline per member of the struct. For example:

struct UserMeta:
    member index : felt #: int
    member hash : felt
    member position : Position
end

Members without a type hint will default to string for felt and the struct type for structs.

The above Cairo-lang example outputs:

[
   {
      "name":"UserMeta",
      "members":[
         {
            "type":"int",
            "name":"index"
         },
         {
            "type":"string",
            "name":"hash"
         },
         {
            "type":"Position",
            "name":"position"
         }
      ],
      "type":"struct"
   }
]

Adding hints to functions

Function hint comments mimic Cairo-lang function type declarations and are placed as the first statement in a function body. For example:

#: (index : int, position : Position) -> (user : User)

@view
func get_user_by_index {
    syscall_ptr : felt*, pedersen_ptr : HashBuiltin*,
    range_check_ptr
    } (index : felt, position : Position) -> (user : User):
    #: (index : int, position : Position) -> (user : User)
    let (hash) = users_index_to_hash.read(index)
    let (user) = get_user_by_hash(hash)
    return (user = user)
end

The above Cairo-lang example outputs:

[
    {
      "name":"get_user_by_index",
      "inputs":[
         {
            "type":"int",
            "name":"index"
         },
         {
            "type":"Position",
            "name":"position"
         }
      ],
      "outputs":[
         {
            "type":"User",
            "name":"user"
         }
      ],
      "type":"function"
   }
]

Development

Install and switch to python 3.9.x

$ pyenv install 3.9.9
$ pyenv local 3.9.9

Create a virtual environment and activate it

$ python -m venv env
$ source venv/bin/activate

Do some awesome work!

Build and publish the package

$ python setup.py bdist_wheel sdist
$ twine upload dist/*