if else then

if else then

Conditional statements.

if <true> else <false> then

if <true> then

Pops a value from the stack, if non-zero execute the true case. Otherwise execute the false case if any. In Haiku Forth, the data-stack and return-stack depth in both cases of the conditional must remain the same.

Examples:

• 1 .5 > if 3 else 4 then → 3
• 3 1 .5 > if 1 + then → 4

Forth Haiku Glossary