Hello, World!

This chapter walks you through creating your first [QED Smart Contract Language] program.

Creating a New Program

Create a new project:

dargo new hello_world

fn main(x: Felt, y: Felt) {
    assert(x == y, "x != y");
}

#[test]
fn test_main() {
    main(1, 1);

    // Uncomment to make test fail
    // main(1, 2);
}

Compiling

run the program using the compiler:

dargo compile

You will see a target directory. Open the hello_world.json inside and you'll be able to see the target code for qed. The qed smart contract language generates this code for each function in the contract and deploys it to the blockchain.

[
    {
        "name": "main",
        "method_id": 680917438,
        "circuit_inputs": [
            0,
            1
        ],
        "circuit_outputs": [],
        "state_commands": [],
        "state_command_resolution_indices": [],
        "assertions": [
            {
                "left": 4294967296,
                "right": 4294967297,
                "message": "x != y"
            }
        ],
        "definitions": [
            {
                "data_type": 0,
                "index": 0,
                "op_type": 0,
                "inputs": [
                    0
                ]
            },
            {
                "data_type": 0,
                "index": 1,
                "op_type": 0,
                "inputs": [
                    1
                ]
            },
            {
                "data_type": 1,
                "index": 0,
                "op_type": 13,
                "inputs": [
                    0,
                    1
                ]
            },
            {
                "data_type": 1,
                "index": 1,
                "op_type": 2,
                "inputs": [
                    1
                ]
            }
        ]
    }
]

Running