AutoCall schedules a function to run automatically on a timer, measured in milliseconds – no threads, no manual frame-counting. It's the tidy answer to "do this every so often": a clock that updates once a second, an enemy wave every ten seconds, a one-off message after a short delay.

AutoCall UpdateClock Every 1000     ' call UpdateClock() every 1000ms (repeats)
AutoCall SpawnWave   Once  10000    ' call SpawnWave() once, 10000ms from now
StopCall UpdateClock                ' cancel a repeating timer
StopCall All                        ' cancel every timer

The handler is a plain Function with no arguments, referred to by name (no parentheses). Every repeats until you stop it; Once fires a single time and removes itself.

Global ticks:Int = 0

Function OnTick()
    ticks = ticks + 1
    Print "Tick {%ticks}"
EndFunction

Function Main()
    AutoCall OnTick Every 500       ' twice a second
    ; ... keep the program running (see below) ...
    Return False
EndFunction

• One timer per function. Calling AutoCall again for the same function just re-arms it – it never stacks up duplicates.
• Handlers run to completion. A handler finishes before the next timer can fire; timers never interrupt each other.
• Missed ticks are skipped, not queued. If the program is busy when a tick is due, that tick is dropped rather than piling up – no runaway catch-up.
• The interval is an expression, so Every (fps * 2) works, not just literals.

A timer only fires while the program is alive to check it. That plays out differently on the two targets:

• Desktop – a program ends as soon as Main() returns. So a timer-driven desktop program keeps a loop running; the scheduler is checked automatically on each pass of any loop (and on every function call), so timers keep ticking as the program works.
• Web – the browser keeps running after Main() returns, so you simply set up your timers and return. The browser's frame loop drives the ticks and nothing blocks. (A long blocking loop on the web would instead freeze the page, so prefer the set-and-return style there.)

Desktop – loop until done:

Function Main()
    AutoCall OnTick Every 500
    Repeat
    Until ticks >= 6          ' the loop keeps the scheduler ticking
    StopCall OnTick
    Return False
EndFunction

Web – set timers and return (the handler stops itself):

Function OnTick()
    ticks = ticks + 1
    Print "Tick {%ticks}"
    If ticks >= 6
        StopCall OnTick
    EndIf
EndFunction

Function Main()
    AutoCall OnTick Every 500
    Return False             ' the browser keeps the timers firing
EndFunction

The hand-rolled alternative – If frameCount Mod 50 = 0 scattered through the main loop – breaks the moment the frame rate changes. AutoCall ... Every 1000 is tied to real elapsed time, so it stays correct whether the program runs fast or slow.

• AutoCall <function> Every <ms> – repeating timer
• AutoCall <function> Once <ms> – one-shot timer
• StopCall <function> (or StopCall All) – cancel
• Handlers are named, no-argument Functions; one timer per function; run to completion
• Desktop keeps a loop alive; Web sets timers and returns

• Functions - the handlers AutoCall runs
• Control Flow - loops that keep a desktop program alive
• Variables & Data Types - string interpolation ({%ticks})

See AutoCall.bam. (The Windows documentation also points at an AutoCall_web.bam; the web target is not part of this edition, so that example is not shipped here.)

BambooBasic © 2026 Michael Denathorn