when

when( 
g_condition 
g_expr1 ... 
) 
=> g_result / nil 

Description

Evaluates a condition. If the result is non-nil, evaluates the sequence of expressions and returns the value of the last expression. This is a syntax form.

If the result of evaluating g_condition is nil, when returns nil.

Arguments

g_condition	Any SKILL expression.
g_expr1	Any SKILL expression.

Value Returned

g_result	Value of the last expression of the sequence g_expr1 if g_condition evaluates to non-nil.
nil	If the g_condition expression evaluates to nil.

Examples

x = -123
when( x < 0 
   println("x is negative")
   -x)
=> 123            ;Prints "x is negative" as side effect.

when( x >= 0
    println("x is positive")
    x)
=> nil

Related Topics

Flow Control Functions

cond

if

unless

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