unless-then: Infix unless-then logic
In postlogic: Infix and Postfix Logic Operators

Description Usage Arguments See Also Examples

These give logic that can be used as a qualifying statement that occurs after the value statement. Take note that the ' as other custom infix operators and so care should be taken that the effect is as desired.

1 2	prior %unless% proposition prior %unless% proposition %then% alternate

`prior`	Value to be returned unless proposition returns FALSE.
`proposition`	The logical statement to condition on.
`alternate`	When proposition returns true and the the alternate value is returned.
`prior %unless% proposition`	An `%if%` statement.

Other postlogic: if-otherwise

    x <- 4
    x <- sqrt(x) %unless% is.complex(x) %then% "This is too hard :("
    x # 2

    x <- 4i
    x <- sqrt(x) %unless% is.complex(x) %then% "This is too hard :("
    x # This is too hard :(