A Forc Project

To initialize a new project with Forc, use forc init:

forc init my-fuel-project

Here is the project that Forc has initialized:

$ cd my-fuel-project
$ tree .
├── Cargo.toml
├── Forc.toml
├── src
│   └── main.sw
└── tests
    └── harness.rs

Forc.toml is the manifest file (similar to Cargo.toml for Cargo or package.json for Node), and defines project metadata such as the project name and dependencies.

For additional information on dependency management, see: here.

authors = ["User"]
entry = "main.sw"
license = "Apache-2.0"
name = "my-fuel-project"


Here are the contents of the only Sway file in the project, and the main entry point, src/main.sw:


abi MyContract {
    fn test_function() -> bool;

impl MyContract for Contract {
    fn test_function() -> bool {

The project is a contract, one of four different project types. For additional information on different project types, see here.

We now compile our project with forc build, passing the flag --print-finalized-asm to view the generated assembly:

$ forc build --print-finalized-asm
ji   i4
lw   $ds $is 1
add  $$ds $$ds $is
lw   $r1 $fp i73              ; load input function selector
lw   $r0 data_1               ; load fn selector for comparison
eq   $r0 $r1 $r0              ; function selector comparison
jnzi $r0 i11                  ; jump to selected function
rvrt $zero                    ; revert if no selectors matched
lw   $r0 data_0               ; literal instantiation
ret  $r0
data_0 .bool 0x01
data_1 .u32 0x2151bd4b

  Compiled contract "my-fuel-project".
  Bytecode size is 68 bytes.

To test this contract, use forc test:

$ forc test
running 1 test
test can_get_contract_id ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.22s

The forc test command tests the contract using the Rust SDK test harness that lives under tests/. The default test harness harness.rs contains boilerplate code to get you started but doesn't actually call any contract methods. For additional information on testing contracts using the Rust SDK, refer to the Testing with Rust section.