OpenEuphoria

Re: Example where Euphoria defaults on a boolean expression

• Posted by 1evan at sbcglobal.net Nov 23, 2002
• 634 views

Rom wrote:

>
>      atom e, 
>
>      e = 2  -- what he asked for
>      f = 3 -- what you gave him
>      if (f = e) and not ( f != e) then print( 1, 1)
>      else print ( 1, 0)
>      end if
>
>      object line
>      line = gets( 0)
>
>
>The Euphoria program returns "0" ...... which is wrong!
>
>"not E and E" is unsolvable, neither true nor false. 
>Euphoria cannot handle this (like C and Pascal).
>
>Rom
>
In boolean logic, there are two possible states: True and False, 1 and 0.
If E = 1(True) then not E = 0(False)
0 and X (either 1 or 0) is always 0(False)
not E and E = 0
0 and 1 = 0

If E = 0(False) then not E = 1(True)
not E and E = 0
1 and 0 = 0

(3 = 2) is 0(False)  
not (3 != 2)  is 0(False)   -- (3 != 2) is 1(True),  not(1) is False(0)
(3 = 2) and not(3 != 2) is 0(False)  -- 0 and 0 is 0(False)