input := ""
stack := List clone
should_quit := false

ops := Map clone

doFile("operators.io")

fns := Map clone

doFile("functions.io")



isnan := method(x, x asNumber != x asNumber)

pop := method(
	stack pop
)
push := method(x,
	if(x != nil,
		stack append(x)
	)
)

print_stack := method(
	stack foreach(v, write(v, ", "))
	write("\n")
)

read := method(
	if(should_quit, return)

	input = File standardInput readLine

	doall(input)

	print_stack
)

action_queue := List clone

doall := method(line,
	action_queue = line splitNoEmpties
	while(action_queue size > 0,
		action := action_queue removeAt(0)
		doword(action)
	)
)

doword := method(word,
	if(isnan(word), exec(word), push(word asNumber))
)

exec := method(op,
	if(op at(0) asCharacter == "'",
		push(op exSlice(1))
		return
	)

	if(op == "defun",
		name := pop

		code := stack clone
		stack empty

		add_fn(name, block(
			code foreach(v, doword(v))
		))

		return
	)

	if(ops hasKey(op), 
		action := ops at(op)
		result := action call(pop, pop)
		push(result)

		return
	)

	if(fns hasKey(op),
		action := fns at(op)
		action call

		return
	)
)

if(System args size > 1,
	file := File with(System args at(1)) openForReading
	doall(file contents)
)

print_stack
while(should_quit == false, read)