HaloO,
Nicholas Clark wrote:
I think that Larry is referring to slightly larger and more expensive rockets
than regular fireworks: http://www.siam.org/siamnews/general/ariane.htm
I know. But where would we put Perl 6 onto a range of programming
languages parrallel to rockets ranging from
HaloO,
Larry Wall wrote:
And replying to the thread in general, I'm not in favor of stricter
default rules on undef, because I want to preserve the fail-soft
aspects of Perl 5.
Also replying to the thread in general, I feel that undef as a
language concept mixes too many usefull concept into
On Thu, Dec 22, 2005 at 02:00:49PM +0100, TSa wrote:
HaloO,
Larry Wall wrote:
but you do not want your rocket control software
throwing unexpected exceptions just because one of your engine
temperature sensors went haywire. That's a good way to lose a rocket.
But then again you might
Uri == Uri Guttman [EMAIL PROTECTED] writes:
Uri sorting in p6 is not at all like in p5. instead of coding up an explicit
Uri comparison code block and duplicating all the key access code (for $a
Uri and $b), you will specify how to extract/generate each key for a given
Uri record. this new
RLS == Randal L Schwartz merlyn@stonehenge.com writes:
Uri == Uri Guttman [EMAIL PROTECTED] writes:
Uri sorting in p6 is not at all like in p5. instead of coding up an explicit
Uri comparison code block and duplicating all the key access code (for $a
Uri and $b), you will specify how to
Uri == Uri Guttman [EMAIL PROTECTED] writes:
Uri i will let damian handle this one (if he sees it). but an idea would be
Uri to allow some form ofkey extraction via a closure with lazy evaluation
Uri of the secondary (and slower) key.
I still don't see that. I understand about the lazy key
RLS == Randal L Schwartz merlyn@stonehenge.com writes:
Uri == Uri Guttman [EMAIL PROTECTED] writes:
Uri i will let damian handle this one (if he sees it). but an idea would be
Uri to allow some form ofkey extraction via a closure with lazy evaluation
Uri of the secondary (and slower) key.
On Wed, Dec 21, 2005 at 10:25:09AM -0800, Randal L. Schwartz wrote:
Uri == Uri Guttman [EMAIL PROTECTED] writes:
Uri i will let damian handle this one (if he sees it). but an idea would be
Uri to allow some form ofkey extraction via a closure with lazy evaluation
Uri of the secondary (and
On Fri, 16 Dec 2005, Darren Duncan wrote:
An undefined value is NOT the same as zero or an empty string respectively;
the latter two are very specific and defined values, just like 7 or 'foo'.
[snip]
Therefore, I propose that the default behaviour of Perl 6 be changed or
maintained such that:
On Sat, 17 Dec 2005, Darren Duncan wrote:
Undef means don't know, which is distinct from zero, because in the
latter case we explicitly have a value of zero.
But when we don't know we can, and generally do, make reasonable
_guesses_.
Experience has shown that 0 or '' according the context
On Sat, 17 Dec 2005, Darren Duncan wrote:
Actually, I don't like autovivification either, and wish there was a pragma
to make attempts to do it a fatal error; it smacks too much of using
variables that weren't declared with 'my' etc. I prefer to put in the
What has the latter to do with
On Mon, 19 Dec 2005, Michele Dondi wrote:
You have very strong arguments, but I think that Perl becoming more solid
should not come at the expense of practicity. Indeed the single warning I
Speaking of which:
| The connection between the language in which we think/program and the
| problems
On Mon, Dec 19, 2005 at 12:13:04PM +0100, Michele Dondi wrote:
my $x;
$x-{foo}[42][2005]{bar}='quux';
Would you like to have to explicitly and verbosely declare the shape of
the structure held in $x instead?
I would like the option to have to, or to be able to do that, and maybe
to
On Monday 19 December 2005 05:06, Michele Dondi wrote:
Speaking of which:
| The connection between the language in which we think/program and the
| problems and solutions we can imagine is very close. For this reason
| restricting language features with the intent of eliminating programmer
At 2:27 AM -0500 12/17/05, Gordon Henriksen wrote:
I find it useful to distinguish between unassigned and undefined (null).
I think that the whole point of having undef in the first place was
to indicate when a container wasn't assigned to yet, and hence has no
useable value. Also, that
On 12/17/05, Darren Duncan [EMAIL PROTECTED] wrote:
An undefined value is NOT the same as zero or an empty string
respectively; the latter two are very specific and defined values,
just like 7 or 'foo'.
I definitely agree with you in principle. This is something that has
been bugging me, too.
At 9:30 AM + 12/17/05, Luke Palmer wrote:
On 12/17/05, Darren Duncan [EMAIL PROTECTED] wrote:
Undef, by definition, is different from and non-equal to everything
else, both any defined value, and other undefs.
You said by definition, but where is this definition?
Maybe definition was
-language@perl.org
Subject: Re: handling undef better
At 10:07 PM -0800 12/16/05, chromatic wrote:
On Friday 16 December 2005 18:15, Darren Duncan wrote:
0. An undefined value should never magically change into a defined
value, at least by default.
This is fairly well at odds with the principle
Darren Duncan schreef:
A variable whose value is undefined is still a typed container; eg:
my Int $z; # undef since not assigned to
my Str $y; # undef since not assigned to
If 'undef' becomes 'fail' at the same time that those base types don't
have default start-values such as 0 and ''
Gordon Henriksen schreef:
I find it useful to distinguish between unassigned and undefined
(null).
I am not sure that you need this distinction, but it should be no
problem to have it, just like 'tainted' and 'NaN' and 'zero/empty' and
'error'.
I find null propagation frustrating; it's more
On 12/16/05, Darren Duncan wrote:
The root question of the matter is, what does undef mean to you?
To me it means nothing. (I'm so callous.)
The fact is, that in any normal program, using an undefined value as
if it were a defined one is a bug. Normally there will be a point
where such a
On 12/17/05, Darren Duncan [EMAIL PROTECTED] wrote:
[snip]
2. Until a value is put in a container, the container has the
POTENTIAL to store any value from its domain, so with respect to that
container, there are as many undefs as there are values in its
domain; with some container types, this
LP == Luke Palmer [EMAIL PROTECTED] writes:
LP Actually, you can think of undef pretty much as defining
LP autovivification. If you use it as a number, it becomes a number; if
LP you use it as a string, it becomes a string; if you use it as a hash,
LP it becomes a hash; ...
LP
I still think it'd be neat to have a special Undef class of some sort
which can be subclassed and further defined to really DWIM rather than
be stuck with whatever pragmas Perl has graciously built in. Something
like this would require more thinking and speculation -- and it may
hurt performance
On 12/17/05, Sebastian [EMAIL PROTECTED] wrote:
Obviously there are mixed opinions of how undef should be treated and
some won't be happy with what becomes final, so implementing some
intelligent defaults and simple pragmas, but not excluding the ability
to *really* control your undefs,
On Friday 16 December 2005 22:25, Darren Duncan wrote:
At 10:07 PM -0800 12/16/05, chromatic wrote:
This is fairly well at odds with the principle that users shouldn't have
to bear the burden of static typing if they don't want it.
This matter is unrelated to static typing. The state of
DD == Darren Duncan [EMAIL PROTECTED] writes:
DD At 9:30 AM + 12/17/05, Luke Palmer wrote:
You're actually saying that undef either compares less than or greater
than all other objects, which contradicts your earlier point. I'd say
it just fails.
DD At the time I wrote
On Sat, Dec 17, 2005 at 12:12:15PM -0800, Ashley Winters wrote:
: Explicitly nil values wouldn't warn or fail on activities which undef
: does. nil is basically a value which is simultaneously '' and 0 and
: 0.0 and false *and* defined, and allows itself to be coerced with the
: same rules as
Something else I've been thinking about, as a tangent to the
relational data models discussion, concerns Perl's concept of
undef, which I see as being fully equivalent to the relational
model's concept of null.
The root question of the matter is, what does undef mean to you?
To me, it means
Hi,
Overloading undef would be cool. This way Joe Coder can make it act
however he'd like when it's not used in the various contexts or
operations -- string, math, smart ... Basically a pragma (or
something) would define the behavior of all undefs declared within the
given scope. Since each undef
Please scratch that first parahgraph because it's incoherrent and I'm crazy:
Overloading undef would be cool. This way Joe Coder can make it act
however he'd like when it's not used in the various contexts or
operations -- string, math, smart ... Basically we would subclass (something) to
to
On 12/16/05, Darren Duncan [EMAIL PROTECTED] wrote:
Something else I've been thinking about, as a tangent to the
relational data models discussion, concerns Perl's concept of
undef, which I see as being fully equivalent to the relational
model's concept of null.
The relational model doesn't
On Friday 16 December 2005 18:15, Darren Duncan wrote:
Therefore, I propose that the default behaviour of Perl 6 be changed
or maintained such that:
0. An undefined value should never magically change into a defined
value, at least by default.
This is fairly well at odds with the principle
At 11:57 PM -0500 12/16/05, Rob Kinyon wrote:
How many different undefs are there?
That depends on what exactly you are asking.
1. An undef is what you have when a container contains no explicit
value (or junction/etc thereof).
A variable whose value is undefined is still a typed
At 10:07 PM -0800 12/16/05, chromatic wrote:
On Friday 16 December 2005 18:15, Darren Duncan wrote:
0. An undefined value should never magically change into a defined
value, at least by default.
This is fairly well at odds with the principle that users shouldn't have to
bear the burden of
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