wasm-run: execute expressions from argv

[ktye]

Currently wasm-run executes every exported function.
I modified it to execute expressions given as command line arguments in post fix order. e.g.:
wasm-run file.wasm 1 2 neg 3 add (where neg takes one and add takes 2 arguments).

var stack []uint64
	for i := range args {
		if u, e := strconv.ParseUint(args[i], 10, 64); e == nil {
			stack = append(stack, u)
		} else if args[i] == "dump" {
			dump(vm.Memory(), stack[len(stack)-2], stack[len(stack)-1])
			stack = stack[:len(stack)-2]
		} else {
			x, ok := m.Export.Entries[args[i]]
			if !ok {
				panic("unknown func: " + args[i])
			}
			fidx := m.Function.Types[x.Index]
			ftyp := m.Types.Entries[fidx]
			n := len(ftyp.ParamTypes)
			pop := make([]uint64, n)
			copy(pop, stack[len(stack)-n:])
			stack = stack[:len(stack)-n]
			res, e := vm.ExecCode(int64(x.Index), pop...)
			if e != nil {
				panic(e)
			}
			stack = append(stack, u64(res))
			fmt.Printf("%s %v: %v(%x)\n", args[i], pop, res, res)
		}
	}

Maybe you find it useful.
(i use it in my wasm compiler for a custom language: https://github.com/ktye/i/tree/master/_/w)