def <result> = fold <index> = <start> to <end> [ with <variable> [ = <init> ] ] [ while <condition> ] do <expression>;

<value1> is <greater/less> than or equal to <value2>

<value1> is [not] equal to <value2>


1. This reserved word is used to define an interval to be used when calculating the fold function. For more information, see the fold reserved word article.

2. This reserved word is also used with is operator in combination with word equal to test if a variable is equal to a certain value.