Test integerness: Difference between revisions

=={{header|PicoLisp}}==

Pico Lisp uses as built in datatype scaled fixed-point numbers. Every number is stored an an Integer and is a non integer only relative to the scale use. For this example we assume that all numbers are generated with the same scale. This is the standard case.

<lang PicoLisp>

(de int? (N)

(= N (* 1.0 (/ N 1.0)))) #returns T or NIL

(de integer? (N)

(and (= N (* 1.0 (/ N 1.0))) N)) #returns value of N or NIL

(scl 4) #-> 4

1.0 #-> 10000

(int? 1.0) #-> T

(int? 1) #-> NIL # 1 with a scale of 4 is same as 0.0001 which is not an Integer

(int? -1.0) #-> T

(int? -0.0) #-> T

(int? "RE") #-> "RE" -- Number expected

(int? (*/ 2.0 1.0 3.0)) #-> NIL # 6667 is not an integer of the scale of 4, use of */ because of the scale

</lang>