while

Evaluates an expression as long as a different expression evaluates to true.

Syntax

• while(cond, expr)

  • cond is an expression

  • expr is an expression

Description

while(cond, expr) evaluates expr repeatedly as long as cond evaluates to true. More precisely, while(cond, expr) first evaluates cond. If the result is false, then while returns. Otherwise, expr is evaluated. Then the process repeats, until cond returns false. while always returns null; hence, it is used only for its side effects.

Examples

f ≔ n ↦ if(even(n), n/2, 3⋅n + 1);
st ≔ n ↦ (c ≔ 0; k ≔ n; while(k ≠ 1, (k ≔ f(k); inc(c))); c);
WordWrap(join(SequenceList(100) @ st))

0, 1, 7, 2, 5, 8, 16, 3, 19, 6, 14, 9, 9, 17, 17, 4, 12, 20, 20, 7, 7, 15, 15,
10, 23, 10, 111, 18, 18, 18, 106, 5, 26, 13, 13, 21, 21, 21, 34, 8, 109, 8, 29,
16, 16, 16, 104, 11, 24, 24, 24, 11, 11, 112, 112, 19, 32, 19, 32, 19, 19, 107,
107, 6, 27, 27, 27, 14, 14, 14, 102, 22, 115, 22, 14, 22, 22, 35, 35, 9, 22,
110, 110, 9, 9, 30, 30, 17, 30, 17, 92, 17, 17, 105, 105, 12, 118, 25, 25, 25

See also

• ForEach

• for

• until

• repeat

• break

• continue