1. Re: Eu's poor design(Irv)
Jim wrote:
> On Sun, Aug 17, 2003 at 08:28:00AM -0700, eugtk at yahoo.com wrote:
<snip>
>> Speaking of arrays, it's pretty well accepted that
>> arrays of characters (AKA "strings") are also useful
>> in computer programming. So how do you tell Eu to
>> create a variable that *must* be a string? Not one
>> that could be a string, or might just as easily be an
>> array of coordinates, or a list of pointers to C
>> routines ?
>
> Another flaw. OE will have a char type and the keyword "string" will mean
> the same thing as "sequence of char".
I also regard a "string" aka "sequence of char" type as desirable and
very useful. So what is a "char"? Traditionally, this is an integer in
the range [0,255]. But I think a programming language nowadays should
handle Unicode strings as well.
So will OpenEu also have a "uni_string" aka "sequence of uni_char"?
<snip>
>> 2. What's worse, even after you have written that
>> complex type-checking routine, once you detect an
>> invalid assignment, there's nothing you can do about
>> it
>> except to crash! Wasn't it QBasic that had a
>> "redo-from-start" error message that at least let
>> you try again, rather than losing your work?
>
> Well, you could make the type-check routine set a flag and return true
> (i.e. pretend its ok but give set a warning so later code can fix it) but
> thats a bit ugly.
IMHO it's much cleaner to use what IIRC is called "explicit type-checking":
---------------------------------------------
type foo (object x)
return integer(x) and (x < 327)
end type
atom data
data = <whatever>
if not foo(data) then
<handle this error however you want>
end if
---------------------------------------------
<snip>
Regards,
Juergen
--
The difference between men and boys
is the price of their toys.
