Re: Some questions about using NaN and Inf
In article <[EMAIL PROTECTED]>, Darren Duncan <[EMAIL PROTECTED]> wrote: > At 3:20 PM -0500 10/6/07, brian d foy wrote: > >For comparisons, how are we going to use Inf and NaN? Are those going > >to be special flyweight objects, so: > > > >$x = 1 / 0; > > > >$x == Inf;# is it the same value > >$x === Inf; # it is always the same object > them. By contrast, the =:= operator always tests if 2 things are the > same object or not, even for those of value types. Maybe the belongs in "Comparison types" in S02 too :) So, then, back to the question. People don't care how it's implemented (and it would be great if we didn't have to explain it). What's the idiom for the comparison going to be?
Re: Some questions about using NaN and Inf
In article <[EMAIL PROTECTED]>, Moritz Lenz <[EMAIL PROTECTED]> wrote: > brian d foy wrote: > > * If I can match $x to NaN (or its stand-in), what happens when $x is > > undef? > > undef is a property of the container variable (that it holds no value), > whereas NaN is a property of the content (like 1/0). so undef ~~ NaN > should be false IMHO. That's fine, but the question people are going to ask is "if undef isn't a number, why doesn't iot match 'not a number'". If it doesn't match, we have to talk about internals to explain it, which is generlaly not a good idea for beginners :)
Re: Pair notation for number radix
On 10/6/07, brian d foy wrote: That looks like it might mean that these are corresponding forms: 8 => 377:8<377>:8(377) Now, if I can do that, what happens to the pair form in a hash composer when I want the key of '8' and the value of :10<377>? What happened to the suggestion of using ` to designate units? Bases are a kind of unit (sort of -- counting the number of 10's or 2's or 16's), so if the colon-form is ambiguous, perhaps it could be 20`16==32`10? -David
Re: Indirect objects, adverbial arguments and whitespace
On 10/7/07, Mark J. Reed <[EMAIL PROTECTED]> wrote: > I would argue for disallowing the all-jammed-together case, lest we > run into longest-match arguments where "foobar:baz" is "foobar: baz" > but "foo:barbaz" is "foo :barbaz". Yuck. Uh, that doesn't make sense. Longest match arguments are leftmost, so if you consider the indirect object : to be part of the variable before it (I wouldn't), then you would always get the "foobar: baz" / "foo: barbaz" interpretation. I don't know about the all jammed together case, but mangle $foo : a is not ambiguous because : a is not a pair: there is no whitespace allowed between the colon and the name on that style of pair. Luke
Re: Indirect objects, adverbial arguments and whitespace
Visually, I interpret ":a" as a token unto itself, though that's probably Ruby's fault. That interpretation would man that the dual-whitespace version would have to be an indirect object. I would argue for disallowing the all-jammed-together case, lest we run into longest-match arguments where "foobar:baz" is "foobar: baz" but "foo:barbaz" is "foo :barbaz". Yuck. On 7 Oct 2007 12:22:56 -, Markus Laker <[EMAIL PROTECTED]> wrote: > If I've got this right: > > mangle $foo :a;# mangle($foo, a => 1); > mangle $foo: a;# $foo.mangle(a()); > > So these -- > > mangle $foo:a; > mangle $foo : a; > > are ambiguous and, as far as I can tell from the synopses, undefined. So > what's the rule: that indirect-object colon needs whitespace after but not > before, and adverbial colon needs whitespace before but not after? > > The reason I ask is that I'm knocking up an intro to Perl 6 for C and C++ > programmers. I expect some of Perl 6's whitespace rules to trip up people > used to C++ (as they have me, in my clumsy attempts with Pugs), and I'd > like to summarise all the whitespace dwimmery in one place. > > Many thanks, > > Markus > -- Mark J. Reed <[EMAIL PROTECTED]>
Indirect objects, adverbial arguments and whitespace
If I've got this right: mangle $foo :a;# mangle($foo, a => 1); mangle $foo: a;# $foo.mangle(a()); So these -- mangle $foo:a; mangle $foo : a; are ambiguous and, as far as I can tell from the synopses, undefined. So what's the rule: that indirect-object colon needs whitespace after but not before, and adverbial colon needs whitespace before but not after? The reason I ask is that I'm knocking up an intro to Perl 6 for C and C++ programmers. I expect some of Perl 6's whitespace rules to trip up people used to C++ (as they have me, in my clumsy attempts with Pugs), and I'd like to summarise all the whitespace dwimmery in one place. Many thanks, Markus
