Using "define <name> = ... enddefine"

There is an alternative syntax that is often useful when existing procedures are being used to create new procedures. We have already used it in defining closures, above:

    define
        then <name of procedure>
        then =
        then an expression evaluating to a procedure
        then
    enddefine;

    define pr_sqrt = sqrt <> pr enddefine;

    pr_sqrt(16);
    4.0

    define list_of_doubles =
        maplist(%procedure (x); x + x endprocedure%)
    enddefine;

    list_of_doubles([1 2 3 4]) =>
    ** [2 4 6 8]

    define father_of =
        newproperty([[tom joe][mary joe][harry dick]],100,false,true)
    enddefine;

    father_of("mary") =>
    ** joe
    father_of("joe") =>
    ** <false>