OpenEuphoria

Re: atom() ambiguity

• Posted by "Carl R. White" <C.R.White at SCM.BRAD.AC.UK> Jun 22, 1998
• 654 views

On Fri, 19 Jun 1998, Daniel Berstein wrote:

> constant true=1
> constant false=0
>
> or type:
>
> type boolean (integer x)
>     if x then            -- If 'x' is != 0
>         return 1
>     else
>         return 0        -- If x = 0
> end type

This code won't work. A program would crash if it a boolean was set to
false(0) and wouldn't crash if x = 7 (for instance).

After thinking a lot recently, this is the best solution (IMHO):

constant TypeFail = 0
constant True = 1, False = 0

type boolean(object x)
    if not integer(x) then
        return TypeFail
    end if
    return x=not(not x)
end type

-- Example code
boolean a,b,q

a = True
b = False
q = (a or b) and not (a and b)

--
Carl R White
E-mail...: cyrek- at -bigfoot.com              / Remove the hyphens before
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