Add injection of asset amount (call parameter) into wallet within playground contract interface.

[Antony Burrows]

Problem Description:

Using the contract interface to send an amount of some asset (in this case BASE_ASSET_ID) via the contract interface call does not seem to have the ability to inject or add an amount (to send in to a contract via call params) via the wallet.

i.e., The below function in Sway has the ability to accept within the call parameters a amount of BASE_ASSET_ID :

    #[storage(read, write)]
    fn receive_funds() {
        if msg_asset_id() == BASE_ASSET_ID {
            storage.balance += msg_amount();
        }
    }

Using fuels-rs this is done with a simple example:

    let contract_instance = MyContract::new(_contract_id.into(), wallet.clone());

    let tx_params = TxParameters::default()
        .set_gas_price(1)
        .set_gas_limit(1_000_000)
        .set_maturity(0);

    let deposit_amount = 1_000_003;

    let call_params = CallParameters::default()
        .set_amount(deposit_amount)
        .set_asset_id(BASE_ASSET_ID);

    let res = contract_instance
        .methods()
        .receive_funds()
        .tx_params(tx_params)
        .call_params(call_params).unwrap()
        .call()
        .await;

However, when using sway-playground, there is no way for the user making the call to this function (receive_funds()) via the contract interface and add an "amount" to the transaction that is being signed.