Conditional

Ternary condition

Symbol: ?
Usually takes 3 parameters: condition, true branch expression and false branch expression.

? true 2 1

Example:

= value

? (> 2 1) "Greater" "Less"

If you pass this operator with only 2 parameters the third one is undefined:

? (== value 0)

<- (console.log 'Zero!')

? (> value 10)

<- (console.log "Greater")

<- (console.log "Less")

Condition with return

Symbol: ?!
Takes 2+ parameters: condition and returnable true branch expression.

Returnable conditional operator ?! is used in sync/async functions and sync/async computations to return value by some condition. E.g., the following code in function will return "One" if number equals 1:

-> (number)

?! (== number 1) "One"

"Two"

This operator can have multiline returnable block:

?! (== number 1)

= a 1

= b 2

+ a b

Operator ?! can't be used as the last or single operator of any block. The folling example shows WRONG usage.

= func -> ()

?! (> 2 1) 'A'

= value <-

?! (> 2 1) 'B'