WHILE

Runs a block again and again, while a condition is true.

Syntax

WHILE condition BEGIN … END

Argument	Meaning
condition	An expression that is `TRUE` or `FALSE` (or a number: 0 is false), worked out before each time round.

DO may go before BEGIN.

Examples

X0 = 10
WIDTH = 10
WHILE X0 + WIDTH <= L BEGIN
    P10 = [X0, 0] ; P11 = [X0 + WIDTH, 0]
    LINE P10, P11
    X0 = X0 + WIDTH * 2
    WIDTH = WIDTH * 1.5
END

WHILE example

Dashes, each half as long again as the one before, as many as fit along the box.

Notes

A loop that never ends stops after a million statements, with the reason shown. BREAK leaves the loop; CONTINUE goes on to the next time round.