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Control blocks

Control blocks decide when and how often other blocks run: loops, conditionals, waiting, stopping, and clones. Several of them are C blocks that wrap the blocks placed inside.

Waiting​

  • wait 1 seconds pauses the script for a time.
  • wait until <condition> pauses until a boolean becomes true.

Loops​

  • repeat 10 runs the wrapped blocks a set number of times.
  • forever runs the wrapped blocks endlessly (a cap block, nothing follows it).
  • repeat until <condition> runs the wrapped blocks until the boolean becomes true.

Conditionals​

  • if <condition> then runs the wrapped blocks only when the boolean is true.
  • if <condition> then ... else runs the first branch when true, the second when false.

Stopping and clones​

  • stop all / this script / other scripts in sprite halts scripts. all stops the whole project.
  • when I start as a clone (hat) runs when a clone of this sprite is created.
  • create clone of myself / sprite makes a running copy of a sprite.
  • delete this clone removes the clone running this script (a cap block).

Bilup and TurboWarp extras​

These control blocks are not in stock Scratch's palette:

  • while <condition> runs the wrapped blocks as long as the boolean stays true (the opposite of repeat until).
  • for each item in 10 runs the wrapped blocks once per count, setting a variable to 1, 2, 3, and so on.
  • all at once runs the wrapped blocks without any screen-refresh yielding, in one frame. It is kept mainly for compatibility; a normal script under warp behaves the same way.
  • switch expression, case value, default, and break build a switch statement: the matching case branch runs, and plain cases stop at the next case (no fall-through unless you add break behaviour). See Bilup extras for details.
  • counter, increment counter, and set counter to 0 are a lightweight built-in counter carried over from Scratch 2 (reporter, stack, and reset). They avoid needing a variable for simple counting.

See also​