Re: request for change of boolean
Kat wrote:
>
> Derek Parnell wrote:
> >
> > I disagree because by showing a specific example gave us some insight in to
> > the way you are thinking, and that can't be a bad thing. However, in this
> > specific
> > example, it also showed us that you had a misunderstanding of the way that
> > the
> > open() function works. It does not return a boolean and thus your argument
> > was
> > weakened. It returns EITHER a valid file handle (a positive integer) OR an
> > error
> > flag (-1).
>
> I fully realise it returns a -1 when error, but i mistakenly hoped -1 could
> be called FALSE, so when i used the filehandle as a boolean, the code would
> run and read smoothly. The same happens when decrementing a flag or index, and
> testing it later: it becomes TRUE again when it goes negative. This just
> smells
> counter intuitive to me. For operations like open(), i consider non-positive
> numerals as "there", but they are error codes, not indicators of success, but
> that's just in my lil book.
>
> Perhaps i was misremembering pascal, i hope i get a little latitude since i
> stopped writing new code years ago to deal with the dog situation here, when
> my world was consumed with me not being consumed.
>
> I do not remember how pascal typed bytebool, but i seem to remember it was an
> array of bits, which simply couldn't go negative, perhaps a bytebool was a
> 0-255
> byte. But likewise, i seem to be remembering if i typecast a string, mapped
> an array of bytebool (or chars, didn't matter as there's no negative chars)
> onto it, in an attempt to reduce memory needs, booleans still performed as
> expected
> when i stopped using that memory as "string" and began using it as "array of
> bytebool". When they aren't 0-255 bytes, but instead are -127-+127 bytes, in
> Euphoria, as Matt pointed out, they could be negative with lots of bits set
> in that format, so a plain bit test fails to respond as i expect(ed)(s)(ing).
> Unless they were typecast as bytebool in pascal, which did different tests,,
> i dunno.
>
>
> Kat
I just installed the latest FreePascal IDE v2.2.0 from www.freepascal.org, and
remembered your post. Here's what the docs say:
<quote>
Boolean types
Free Pascal supports the Boolean type, with its two pre-defined possible values
True and False.
It also supports the ByteBool, WordBool and LongBool types. These are the only
two values
that can be assigned to a Boolean type. Of course, any expression that resolves
to a boolean
value, can also be assigned to a boolean type. Assuming B to be of type Boolean,
the following
Table 3.3: Boolean types
Name Size Ord(True)
Boolean 1 1
ByteBool 1 Any nonzero value
WordBool 2 Any nonzero value
LongBool 4 Any nonzero value
</quote>
Note to self: Pasting from a .pdf isn't the best way to keep text formatting.
The previous version of FPC I was using had the same text. As I have hardly ever
used bytebools myself, preferring cleaner (imho) booleans, I can't tell how it
worked on other compilers.
CChris
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