Using GetKeyState() and loops - autohotkey

Question

I'm trying to write a script that has a loop in which the upper arrow key is pressed every two seconds. The loop must be activated when I press the spacebar and deactivated when I press it again. I'm now using this.
$Space::
if GetKeyState("Space", "P")
{
Loop
{
Sleep 2000
Send {Up}
if GetKeyState("Space", "P")
{
return
}
}
}
For some reason, the if condition inside the loop doesn't work, i.e. I can't get out of the loop. I hope anyone can help me out...

Answer 1

You wouldn't need the first if GetKeyState("Space", "P")
and you would need to be holding space when the loop got to the second one
for it to break; and you would need to replace the return with break.
However I agree with Gary, although I would write it like this:
; (on:=!on) reverses the value of variable 'on'
; the first press of space reverses on's value (nothing) to something (1)
; the second press reverses on's value from (1) to (0)
; when (on = 1) delay will be set to 2000, and Off when (on = 0)
space::SetTimer, Action, % (on:=!on) ? ("2000") : ("Off")
Action:
Send, {up}
Return
% starts an expression.
From http://l.autohotkey.net/docs/Variables.htm
?:
Ternary operator
This operator is a shorthand replacement for the if-else statement.
It evaluates the condition on its left side to determine
which of its two branches will become the final result.
For example, var := x>y ? 2 : 3 stores 2 in Var if x is greater than y; otherwise it stores 3.

Answer 2

How about using SetTimer?
; Create timer.
SetTimer, SendUp, 2000
; Set timer to 'Off' at start of script.
SetTimer, SendUp, Off
TimerEnabled := False
; When Space is pressed toggle the state of the timer.
$Space::
If TimerEnabled
{
SetTimer, SendUp, Off
TimerEnabled := False
}
Else
{
SetTimer, SendUp, On
TimerEnabled := True
}
; Label called by timer to send {Up} key.
SendUp:
Send, {Up}
return