feat(cheats): ffi

[ZeroEkkusu]

Motivation

When I started using Foundry, I didn't find ffi intuitive. I thought I could give it a command, but, I was supposed to initialize an array first, assign values, etc.

This cheat makes it work the way I thought it did. I'll let you decide if it's worth adding.

Solution

Before

string[] memory inputs = new string[](3);

inputs[0] = "echo";
inputs[1] = "-n";
inputs[2] = "hello world";

bytes memory res = vm.ffi(inputs);

After

bytes memory res = ffi("echo -n", raw("hello world"));

Note: raw passes the text as-is.

Before

string[] memory inputs = new string[](4);

inputs[0] = "yarn";
inputs[1] = "ts-node";
inputs[2] = "path/to/script.ts";
inputs[3] = vm.toString(
    abi.encode(
        user,
        data
    )
);

bytes memory res = vm.ffi(inputs);

After

bytes memory res = ffi(
    "yarn ts-node path/to/script.ts",
    vm.toString(abi.encode(user, data))
);

Note: ffi accepts up to five arguments. Both examples used two.

[mds1]

This is pretty neat and definitely nicer UX, but in the spirit of foundry-rs/foundry#3782 and gradually migrating towards that I'd rather implement this natively in forge and minimize addition of new StdCheats

[ZeroEkkusu]

Alright!