HELP UNTIL Revised by Fran Evelyn, July 85
The statement
until <condition> do <action> enduntil
is equivalent to:
while not(<condition>) do <action> endwhile
It evaluates the condition, and if it is not TRUE executes the <action>. It
then goes back to test the condition again. The iteration continues until
the condition is FALSE. For example
10 -> n;
until n <= 0 do
ppr(n)
n - 1 -> n
enduntil;
will print out (see HELP *PPR):
10 9 8 7 6 5 4 3 2 1
The iteration can be terminated using any of
* RETURN, * QUITLOOP, *QUITIF, * QUITUNLESS
or re-started using
* NEXTLOOP, * NEXTIF, * NEXTUNLESS
See HELP
*LOOPS - for other types of iteration
*WHILE - for iteration until a condition evaluates as false
*FOR - iteration over numbers or structures
*CONTROL - for an overview of control facilities
See also
REF * SYNTAX, REF * POPSYNTAX
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