Learn WAT with Real Code Examples

# wat/demo/add.wat
(module
    (func $add (param $a i32) (param $b i32) (result i32)
        local.get $a
        local.get $b
        i32.add)
    (export "add" (func $add))
)

A basic WebAssembly Text Format (WAT) module that adds two numbers.

# wat/demo/multiply.wat
(module
    (func $multiply (param $a i32) (param $b i32) (result i32)
        local.get $a
        local.get $b
        i32.mul)
    (export "multiply" (func $multiply))
)

A WAT module that multiplies two numbers.

# wat/demo/subtract.wat
(module
    (func $subtract (param $a i32) (param $b i32) (result i32)
        local.get $a
        local.get $b
        i32.sub)
    (export "subtract" (func $subtract))
)

A WAT module that subtracts two numbers.

# wat/demo/factorial.wat
(module
    (func $factorial (param $n i32) (result i32)
        (local $result i32)
        (local.get $n)
        i32.const 1
        i32.le_s
        if (result i32)
        then i32.const 1
        else
        local.get $n
        local.get $n
        i32.const 1
        i32.sub
        call $factorial
        i32.mul
        end)
    (export "factorial" (func $factorial))
)

A WAT module that calculates factorial recursively.

# wat/demo/fibonacci.wat
(module
    (func $fib (param $n i32) (result i32)
        local.get $n
        i32.const 1
        i32.le_s
        if (result i32)
        then local.get $n
        else
        local.get $n
        i32.const 1
        i32.sub
        call $fib
        local.get $n
        i32.const 2
        i32.sub
        call $fib
        i32.add
        end)
    (export "fib" (func $fib))
)

A WAT module that calculates Fibonacci numbers recursively.

# wat/demo/max.wat
(module
    (func $max (param $a i32) (param $b i32) (result i32)
        local.get $a
        local.get $b
        i32.gt_s
        if (result i32)
        then local.get $a
        else local.get $b
        end)
    (export "max" (func $max))
)

A WAT module that returns the maximum of two numbers.

# wat/demo/min.wat
(module
    (func $min (param $a i32) (param $b i32) (result i32)
        local.get $a
        local.get $b
        i32.lt_s
        if (result i32)
        then local.get $a
        else local.get $b
        end)
    (export "min" (func $min))
)

A WAT module that returns the minimum of two numbers.

# wat/demo/even.wat
(module
    (func $isEven (param $n i32) (result i32)
        local.get $n
        i32.const 2
        i32.rem_s
        i32.eqz)
    (export "isEven" (func $isEven))
)

A WAT module that checks if a number is even.

# wat/demo/odd.wat
(module
    (func $isOdd (param $n i32) (result i32)
        local.get $n
        i32.const 2
        i32.rem_s
        i32.const 0
        i32.ne)
    (export "isOdd" (func $isOdd))
)

A WAT module that checks if a number is odd.

# wat/demo/toggle.wat
(module
    (global $state (mut i32) (i32.const 0))
    (func $toggle (result i32)
        global.get $state
        i32.const 1
        i32.xor
        global.set $state
        global.get $state)
    (export "toggle" (func $toggle))
)

A WAT module that toggles a boolean value between 0 and 1.