Temporal / delta spec
Greetings,
S32/Temporal says a DateTime object can be maniplated like so:
$dt.delta(44, minutes);
Rakudo's core/Temporal.pm contains this:
my enum TimeUnit (
:second(1), :seconds(2),
:minute(3), :minutes(4),
[snip]
);
which is used in the signature of both DateTime and Date's delta methods:
method delta($amount, TimeUnit $unit) {
which I think means delta() can't be called outside of the scope of
the Temporal.pm file.
If I try running the synopsis example, I get the following error:
Undeclared routine: minutes used at line 1
The test files
S32-temporal/Date.t and
S32-temporal/DateTime.t
both die on the delta tests.
Should the TimeUnit enumeration be changed to "is export" ?
Rather than export those 14 keys into the global namespace, would it
make more sense for the spec to be something more like this:
$dt.delta( :minute(44) );
using the same argument conventions as DateTime.new() ?
Regards,
Carl
Re: Temporal / delta spec
Hi Carl,
On 02/19/2013 02:03 PM, Carl Franks wrote:
S32/Temporal says a DateTime object can be maniplated like so:
$dt.delta(44, minutes);
Rakudo's core/Temporal.pm contains this:
my enum TimeUnit (
:second(1), :seconds(2),
:minute(3), :minutes(4),
[snip]
);
which is used in the signature of both DateTime and Date's delta methods:
method delta($amount, TimeUnit $unit) {
which I think means delta() can't be called outside of the scope of
the Temporal.pm file.
TimeUnit is accessible outside of this file, because it is part of the
setting, and the setting forms the outer lexical scope for all
user-space programs.
If I try running the synopsis example, I get the following error:
Undeclared routine: minutes used at line 1
Works fine here:
mlenz@mlenz-workstation:~/p6/rakudo$ ./perl6 -e 'say
~DateTime.now.delta(4, hours)'
2013-02-19T18:20:34Z
The test files
S32-temporal/Date.t and
S32-temporal/DateTime.t
both die on the delta tests.
They work fine here. The only explanation that I can find for this
discrepancy between our systems is that your build of Rakudo might be
too old.
What version of Rakudo are you using? (try running perl6 --version)
Rather than export those 14 keys into the global namespace, would it
make more sense for the spec to be something more like this:
$dt.delta( :minute(44) );
using the same argument conventions as DateTime.new() ?
I belive Carl Mäsak is better qualified to answer this question, since
he changed the specs (there used to be a .truncated-to( :minutes ) or
so), but here are two interesting points:
1) while every user-facing program does see those constants, they can
easily redefined in any inner scope, so namespace pollution isn't too
much of a problem
2) Adding deltas of time onto a given point of time is not commutative.
For example First adding a month and then a day can be give you a
different result than first adding a day and then a month. But named
arguments are unordered by nature, which makes them a poor fit for
non-commutative operations.
Cheers,
Moritz
Re: Perl 6 / Rakudo unicode code point ranges
The code points giving you trouble are 0xFDD0..0xFDEF:
http://stackoverflow.com/questions/5188679/whats-the-purpose-of-the-noncharacters-ufdd0-to-ufdef
You can split this into two ranges to avoid the problematic points (and
could use this to combine the distinct ranges you have above.)
$ perl6 -e 'say ?("\c[0xFDCF]" ~~
/<[\c[0xE000]..\c[0xFDCF]\c[0xFDF0]..\c[0xFFFD]]>/)'
True
Note that if you have invalid UTF-8 input, though, you'll still get the
invalid character error, so you'll need to deal with that before trying to
use the rule.
$ perl6 -e 'say ?("\c[0xFDD0]" ~~
/<[\c[0xE000]..\c[0xFDCF]\c[0xFDF0]..\c[0xFFFD]]>/)'
===SORRY!===
Invalid character for UTF-8 encoding
Hope this helps.
On Mon, Feb 18, 2013 at 11:29 PM, David Warring wrote:
> Hi Guys,
> A quick question.
>
> I'm trying to interpret unicode code-point ranges from the CSS 3 spec -
> http://www.w3.org/TR/css3-syntax/#CHARSETS
>
> The rule in question is
>
> nonascii :== #x80-#xD7FF #xE000-#xFFFD #x1-#x10
>
> Where (I think) these are unicode code-point ranges.
>
> The latest rakudo build is fine with:
>
>
> % perl6 -e perl6 -e '/<[\c[0x80]..\c[0xD7FF]]>/'
>
>
> ...but doesn't like the second (or third) range:
>
>
> % perl6 -e '/<[\c[0xE000]..\c[0xFFFD]]>/'
> ===SORRY!===
> Invalid character for UTF-8 encoding
>
>
> ...the individual code points are ok:
>
>
> % perl6 -e '/<[\c[0xE000]]>/'
> % perl6 -e '/<[\c[0xFFFD]]>/'
>
>
> I'm think I'm getting the above error because not all unicode code-points
> are defined for the range xE000 to xFFFD - see
> http://www.utf8-chartable.de/unicode-utf8-table.pl .
>
> I'm just having a problem implementing a concise regex/grammar rule for the
> above. Looking for advice.
>
> Cheers,
> David Warring
>
--
Will "Coke" Coleda
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