OpenEuphoria

Re: type string

• Posted by Daniel Berstein <daber at PAIR.COM> Mar 11, 1999
• 580 views

Here's my recursive solution:

global type string(sequence s)
        integer i
        i = length(s)
        if (i=0) or (integer(s[i]) and (s[i]>0) and (s[i]<=255) and
string(s[1..i-1])) then
                return 1
        end if
        return 0
end type

I haven't benchmarked it, and don't know how penalized are recursive calls.
Anyways Euphoria short-circuit evaluation should stop the recurse as soon
as an invalid entry is detected.

I tried with a direct return statement, but short-circuit evaluation only
works for if and while statements. I understand that short-circuit may
render unwanted results for general purpose boolean operations, but in the
context of a type declaration, where only true/false values can be returned
(same case as if and while) there could be a way to override the default
behaviour. Maybe "with/without short_circuit" keywords could be implemented
Rob. Or even create short-circuit specific boolean operators: sc_or,
sc_and, sc_xor.



Regards,
         Daniel  Berstein
         [daber at pair.com]