Paul Hodges wrote:
--- Jonadab the Unsightly One [EMAIL PROTECTED] wrote:
Consider this test in Perl:
if \0 {...}
Its equivalent in C is this:
if () ...
That can't be right. If anything it's got the two languages
flipped, but that's still not quite right either. Apples and
orange
[EMAIL PROTECTED] (Paul Hodges) writes:
Do note that I realize I can check it. It's just that for no reason I
can quite define, my C background wants a null byte to be FALSE without
any special chicanery on my part when checking. I can live with the
fact it isn't going to be, it just seems odd
Paul Hodges wrote:
Do note that I realize I can check it. It's just that for no reason I
can quite define, my C background wants a null byte to be FALSE without
any special chicanery on my part when checking. I can live with the
fact it isn't going to be, it just seems odd to me.
If that seems odd
Paul Hodges wrote:
--- Spider Boardman [EMAIL PROTECTED] wrote:
You need ord() for character/grapheme/byte/whatever testing that's
equivalent to what C does. Since C doesn't really have strings, and
Perl does, this is just one of those differences between the
languages where (essentially, and
--- Simon Cozens [EMAIL PROTECTED] wrote:
[EMAIL PROTECTED] (Paul Hodges) writes:
Do note that I realize I can check it. It's just that for no reason
I can quite define, my C background wants a null byte to be FALSE
without any special chicanery on my part when checking. I can live
with
--- Jonadab the Unsightly One [EMAIL PROTECTED] wrote:
Paul Hodges wrote:
Do note that I realize I can check it. It's just that for no reason
I can quite define, my C background wants a null byte to be FALSE
without any special chicanery on my part when checking. I can live
with the
--- Brent 'Dax' Royal-Gordon [EMAIL PROTECTED] wrote:
Paul Hodges wrote:
--- Spider Boardman [EMAIL PROTECTED] wrote:
You need ord() for character/grapheme/byte/whatever testing that's
equivalent to what C does. Since C doesn't really have strings,
and Perl does, this is just one of those
On Thu, Jun 24, 2004 at 12:43:30PM -0700, Scott Bronson wrote:
So, in summary, though 0==false appears to work, it leads to a number
of strange boundary conditions and, therefore, bugs. It's hard for new
programmers to grasp and even old hacks are still sometimes tripped up
by it. It just
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Paul Hodges wrote:
| --- Luke Palmer [EMAIL PROTECTED] wrote:
|
|Paul Hodges writes:
|
|So, in P6:
|
| if 0 { print 0\n; } # I assume this won't print.
| if '0' { print '0'\n; } # I assume this won't print.
| if ''{ print ''\n;}
Paul Hodges wrote:
So a null byte is still Boolean true.
Ugh, yarf, ack, etc.
But as long as I know -- easy enough to check explicitly.
But just tell me thisam I the only guy who thinks this *feels*
wierd?
It doesn't feel weird to me, but my previous languages of choice
were fairly high-level
Paul Hodges wrote:
So a null byte is still Boolean true.
But just tell me thisam I the only guy who thinks this *feels*
wierd? Understanding the reason doesn't make it any more ~comfortable~.
I think you are. Perl considers null to be data--it's that simple.
Remember, while Perl can work
At some point in history, Paul Hodges wrote (in part):
ph So a null byte is still Boolean true. Ugh, yarf, ack, etc.
No. And it never has been (at least in my world view). However, asking
that question explains some things. See below for more.
ph But as long as I know -- easy enough to
On Thu, 2004-06-24 at 21:45, Brent 'Dax' Royal-Gordon wrote:
Perhaps not as happy as you think:
my $foo = '0';
my String $bar = '0';
if $foo { say 'foo true' }
if $bar { say 'bar true' }
Would print 'bar true', but not 'foo true'.
Frankly, I love it. Since I plan on
--- Spider Boardman [EMAIL PROTECTED] wrote:
At some point in history, Paul Hodges wrote (in part):
ph So a null byte is still Boolean true. Ugh, yarf, ack, etc.
No. And it never has been (at least in my world view).
A valid point, though I reply:
my $x = \0;
print true if $x;
Every now and then I have this discussion with people at work that involve Perl's
ideas of boolean truth. I usually break it down like this:
In Perl5, the following values are FALSE: undef, '0', 0, and ''.
Anything not in that list is considered TRUE in a boolean context. That means that
In Perl5, the following values are FALSE: undef, '0', 0, and ''.
What you fail to note is that each of these is false for a reason.
undef is false so that you can test an object for truth; if it
is undef it obviously contains no data, so it's false. 0 is false
so that you can test numbers for
On Thu, 2004-06-24 at 08:04, Jonadab the Unsightly One wrote:
In Perl5, the following values are FALSE: undef, '0', 0, and ''.
... The really special case is '0', which
is false for arcane (but very sensible) reasons.
I don't agree that '0' being false is sensible. This, plus less than
On Thu, 2004-06-24 at 10:44, Scott Bronson wrote:
I don't agree that '0' being false is sensible...
I don't mean to imply that I think it's senseless. Just that, to me, it
smells suspiciously like a hack. :)
- Scott
Scott Bronson skribis 2004-06-24 10:44 (-0700):
However, it seems that because Perl is finally getting a typing system,
this hack can be fixed in Perl itself! No programmer intervention
needed. Undef and '' can be false for strings, undef and 0 can be false
for integers, undef, 0, and 0.0
On Thu, Jun 24, 2004 at 08:04:10PM +0200, Juerd wrote:
: Scott Bronson skribis 2004-06-24 10:44 (-0700):
: However, it seems that because Perl is finally getting a typing system,
: this hack can be fixed in Perl itself! No programmer intervention
: needed. Undef and '' can be false for
Scott Bronson writes:
On Thu, 2004-06-24 at 08:04, Jonadab the Unsightly One wrote:
In Perl5, the following values are FALSE: undef, '0', 0, and ''.
... The really special case is '0', which is false for arcane (but
very sensible) reasons.
I don't agree that '0' being false is
Larry Wall skribis 2004-06-24 11:29 (-0700):
This is Perl 6. Everything is an object, or at least pretends to be one.
Everything has a .boolean method that returns 0 or 1. All conditionals
call the .boolean method, at least in the abstract. (The optimizer is
free to optimize the method call
On Thu, Jun 24, 2004 at 08:44:45PM +0200, Juerd wrote:
: Larry Wall skribis 2004-06-24 11:29 (-0700):
: This is Perl 6. Everything is an object, or at least pretends to be one.
: Everything has a .boolean method that returns 0 or 1. All conditionals
: call the .boolean method, at least in the
On Thu, 2004-06-24 at 11:34, Smylers wrote:
Scott Bronson writes:
But you're fine with 0 being false? 0 and '0' are pretty much
interchangeable in Perl 5 -- wherever you can use one, you can use the
other and it gets coerced to it.
Let's back up... Strings and numbers are meant to be
Larry Wall skribis 2004-06-24 12:24 (-0700):
Well, the type/property name doesn't have to be boolean--it could
be truth, instead.
I understand that 'true' and 'false' can't be used.
However, truth is in the same category as definedness, and
$foo.definedness looks awful :)
Perhaps for
Larry Wall wrote:
What do you mean by length?
For a string, it obviously either means number of bytes or number
of characters. Pick one, document it, and let people who want the
other semantic use a pragma.
I don't think it matters which one you pick as default, as long
as it's clearly
On Thu, Jun 24, 2004 at 04:19:25PM -0400, Jonadab the Unsightly One wrote:
: Larry Wall wrote:
:
: What do you mean by length?
:
: For a string, it obviously either means number of bytes or number
: of characters. Pick one, document it, and let people who want the
: other semantic use a
Scott Bronson writes:
On Thu, 2004-06-24 at 11:34, Smylers wrote:
But you're fine with 0 being false? 0 and '0' are pretty much
interchangeable in Perl 5 -- wherever you can use one, you can use
the other and it gets coerced to it.
Let's back up... Strings and numbers are meant to
Larry Wall [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]
This is Perl 6. Everything is an object, or at least pretends to be one.
Everything has a .boolean method that returns 0 or 1. All conditionals
call the .boolean method, at least in the abstract.
My reading of A12 leads me
--- Dave Whipp [EMAIL PROTECTED] wrote:
Larry Wall [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]
This is Perl 6. Everything is an object, or at least pretends to
be one.
Everything has a .boolean method that returns 0 or 1. All
conditionals
call the .boolean method, at
Austin Hastings skribis 2004-06-24 14:29 (-0700):
$foo as boolean
This is Perl 6. Everything is an object, or at least pretends to
be one. Everything has a .boolean method that returns 0 or 1.
If I understand the current design correctly, having both .boolean and
casting via as would mean
--- Juerd [EMAIL PROTECTED] wrote:
Austin Hastings skribis 2004-06-24 14:29 (-0700):
$foo as boolean
This is Perl 6. Everything is an object, or at least pretends to
be one. Everything has a .boolean method that returns 0 or 1.
If I understand the current design correctly, having
Austin Hastings skribis 2004-06-24 15:54 (-0700):
I'd say yeah, it is. 0-but-true is pretty nice to have. (Finally the
system calls can return something other than -1.)
That we already have. 0 but true. (perldoc -f fcntl)
It's 1 but false that's really special :)
Juerd
On Thu, Jun 24, 2004 at 03:24:25PM -0700, Scott Walters wrote:
: I want an okay. Routines should be able to return okay to indicate
: an ambivalent degree of success. okay would be defined as true | false,
Some messages want to be simultaneously Warnocked and not Warnocked...
Larry
-Original Message-
From: Dave Whipp [mailto:[EMAIL PROTECTED]
Sent: Thursday, June 24, 2004 5:22 PM
To: [EMAIL PROTECTED]
Subject: Re: definitions of truth
Larry Wall [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]
This is Perl 6. Everything is an object
On Thu, 2004-06-24 at 14:17, Smylers wrote:
Because the above would've been insane: saying that Csif ($x) treats
$x as a string would be pretending that Cif always treats its
arguments as numbers, but something such as Cif ($x eq 'frog') doesn't
have any numbers in it.
Doesn't it?
perl -e
I seemed to have opened a can of worms, lol
But did anybody see the one that had something to do with my question
crawling around? (I've obviously missed a couple of messages. They're
probably hanging out down at the router in the cyberspace equivelent of
teenagers ogling girls on the street
Paul Hodges writes:
I seemed to have opened a can of worms, lol
But did anybody see the one that had something to do with my question
crawling around? (I've obviously missed a couple of messages. They're
probably hanging out down at the router in the cyberspace equivelent of
teenagers
Juerd wrote:
That we already have. 0 but true. (perldoc -f fcntl)
It's 1 but false that's really special :)
No, what's really special is the ability to return entirely
different things in string versus numeric context, like the
magic $! does in Perl5.
That, or interesting values of undef :-)
--- Luke Palmer [EMAIL PROTECTED] wrote:
Paul Hodges writes:
So, in P6:
if 0 { print 0\n; } # I assume this won't print.
if '0' { print '0'\n; } # I assume this won't print.
if ''{ print ''\n;} # I assume this won't print.
if undef { print undef\n; } # I
Scott Bronson wrote:
That's the plan? Happy day! I was not aware of that. Because I didn't
see anything about this in Perl 6 Essentials, I just figured that
Perl5's '0'==undef was being brought forward into Perl6. The horror!
Sorry for the bad assumption. :)
Perhaps not as happy as you
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