Understanding the WebAssembly Text Format WAT

(module
  (func $add (param $a i32) (param $b i32) (result i32)
    get_local $a
    get_local $b
    i32.add)
  (export "add" (func $add))
)

(module
  (func $add 
    (param $a i32) (param $b i32)
    (result i32)
    get_local $a
    get_local $b
    i32.add)
  (export "add" (func $add))
)

(module
  ;; Define a function to add two 32-bit integers
  (func $add (param $a i32) (param $b i32) (result i32)
    get_local $a
    get_local $b
    i32.add)
  (export "add" (func $add))
)

(module
  ;; Integer addition
  (func $add (param $a i32) (param $b i32) (result i32)
    get_local $a
    get_local $b
    i32.add)

  ;; Floating-point addition
  (func $add_f32 (param $a f32) (param $b f32) (result f32)
    get_local $a
    get_local $b
    f32.add)

  (export "add"      (func $add))
  (export "add_f32"  (func $add_f32))
)

(module
  ;; Add two 128-bit SIMD vectors
  (func $add_vectors (param $v1 v128) (param $v2 v128) (result v128)
    get_local $v1
    get_local $v2
    v128.add)
  (export "add_vectors" (func $add_vectors))
)

(func $add_nonneg (param $a f32) (param $b f32) (result f32)
  get_local $a
  f32.const 0
  f32.lt               ;; compare a < 0
  if (result f32)
    f32.const 0        ;; return 0 if negative
  else
    get_local $a
    get_local $b
    f32.add            ;; otherwise add
  end)

(module
  (func $sum_array (param $ptr i32) (param $length i32) (result i32)
    (local $i i32)    ;; index
    (local $sum i32)  ;; accumulator

    (block $exit
      (loop $loop
        ;; break if $i == $length
        (br_if $exit (i32.eq (get_local $i) (get_local $length)))

        ;; load element and add
        (set_local $sum
          (i32.add
            (get_local $sum)
            (i32.load (get_local $ptr))))

        ;; advance pointer and counter
        (set_local $ptr (i32.add (get_local $ptr) (i32.const 4)))
        (set_local $i   (i32.add (get_local $i)   (i32.const 1)))

        (br $loop)
      )
    )
    (get_local $sum)
  )
  (export "sum_array" (func $sum_array))
)

(module
  (memory 1)  ;; 1 page = 64 KiB

  (func $add_from_mem (result i32)
    i32.load offset=0    ;; load at byte 0
    i32.load offset=4    ;; load at byte 4
    i32.add)

  (export "add_from_mem" (func $add_from_mem))
)

(module
  (memory 1)
  (table 2 anyfunc)

  ;; Define two operations
  (func $add_i32  (param $a i32) (param $b i32) (result i32)
    get_local $a
    get_local $b
    i32.add)
  (func $add_f32  (param $a f32) (param $b f32) (result f32)
    get_local $a
    get_local $b
    f32.add)

  ;; Initialize table entries
  (elem (i32.const 0) $add_i32 $add_f32)

  ;; Type for indirect calls
  (type $i32_add_t (func (param i32 i32) (result i32)))

  (func $call_by_index (param $idx i32) (result i32)
    i32.const 10        ;; first argument
    i32.const 20        ;; second argument
    get_local $idx      ;; table index
    call_indirect (type $i32_add_t)
  )

  (export "add_i32"        (func $add_i32))
  (export "add_f32"        (func $add_f32))
  (export "call_by_index"  (func $call_by_index))
)