making $^V a version object broke functionality #15488
Comments
From @maukeCreated by @maukeperldoc perl5100delta: | $^V is now a "version" object instead of a v-string OK, they must be rewritten. But how? Consider e.g. printf "use feature ':%vd';\n", substr($^V, 0, 2); This is reasonable code with v-strings. How do you do the same thing with a As far as I can see, the version module only provides parsing, pretty-printing, The 5.10 change removed functionality, telling us that the 5.6/5.8 way no As an aside, perldoc -v '$^V' says: | The disadvantage is that prior to v5.10.0, it was only a literal v-string, Which doesn't have any technical basis: You could easily print it using Perl Info |
From @JohnPeacockOn 07/31/2016 10:04 AM, l.mai@web.de wrote:
Perl objects are typically just hashes of stuff, blessed into a class, e.g. $ perl -w -MData::Dumper -E 'say Dumper($^V);' So your code could be rewritten as: printf "use feature ':%d.$d;\n", @{$^V->{version}}[0,1]; v-strings are intrinsically a binary format, so you MUST treat it If you'd like to open a feature request for version.pm to include Thanks John |
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The RT System itself - Status changed from 'new' to 'open' |
From @maukeAm 31.07.2016 um 17:48 schrieb John Peacock:
That's not part of the public API. I'd have to rely on implementation Can this code be written at all using just the public API and without
1. v-strings are normal scalars: they're strings.
I'm not directly concerned with version.pm. I've never had a use for it. My main concern is being able to introspect the version number of the In that case a method to return the numeric components would be nice, as my @parts = $^V->parts; # (5, 24, 0) Would that be good addition to the version.pm API? -- |
From zefram@fysh.orgLukas Mai wrote:
$] has always worked for that, and still does. @parts = map { 0+$_ } sprintf("%010.6f", "$]") =~ /([0-9]{3})/g; -zefram |
From @JohnPeacockOn 07/31/2016 03:46 PM, Lukas Mai wrote:
Actually, the internal representation *is* part of the public API, see
I beg to differ. v-strings are stored as simple scalar but they are an ENQ CAN NUL You cannot print a v-string without the special "%vd" format, which $ perl -MDevel::Peek -E 'say Dump(53.56.48)'
While this is true, it is also misleading, in that you had to already
Then frankly you are using the version module wrong. A version object
The fact that the normal stringification method of version objects is to
Attached is a proposed addition to the public API that provides the use version; before you can use any of these methods. If this would fit your needs, John |
From @JohnPeacockelements.diffdiff -r ba402aa3d3a5 lib/version.pm
--- a/lib/version.pm Wed Aug 03 05:22:30 2016 -0400
+++ b/lib/version.pm Wed Aug 03 06:31:20 2016 -0400
@@ -124,5 +124,36 @@
}
}
+# Helper methods
+sub elements {
+ my ($self) = @_;
+ return ($self->{version});
+}
+sub epoch {
+ my ($self) = @_;
+ my @elements = @{$self->elements};
+ return 'v'.$elements[0];
+}
+
+sub major {
+ my ($self) = @_;
+ my @elements = @{$self->elements};
+ push @elements, 0 while $#elements < 2;
+ return 'v'.join('.', @elements[0,1]);
+}
+
+sub minor {
+ my ($self) = @_;
+ my @elements = @{$self->elements};
+ push @elements, 0 while $#elements < 3;
+ return 'v'.join('.', @elements[0,1,2]);
+}
+
+sub patch {
+ my ($self) = @_;
+ my @elements = @{$self->elements};
+ push @elements, 0 while $#elements < 4;
+ return 'v'.join('.', @elements[0,1,2,3]);
+}
1;
|
From @maukeAm 03.08.2016 um 12:39 schrieb John Peacock:
Wait, version::Internals is supposed to be a public API? You definitely need to document that, then. When something is called Case in point: the $v->{version} field is described in a document called All of this screams "DO NOT USE" (outside of debugging) to me.
Again, this should be documented, then. Neither version nor (Besides, I'd have to rebless $^V, which is a whole nother can of worms.)
I find the current situation even more confusing. "v-strings are just
I'm not using the version module (directly). I'm using the $^V variable, A few days ago I had to (for the first time) do something with perl
($] works fine for fixed values. Why bother with an object then?) My actual use case is this: I have a project (stored in a single My solution was to create a wrapper module that adds a version-dependent Further constraints: I want the subdirectory names to look nice for A while later I came across a second use case: Create a dynamic script Both of these are easy with v-strings: sprintf('v%vd', substr($v, 0, 2))
You seem to have a (harmless) off-by-one error in there: You do 'push The other issue I see is that the methods and names are specific to $^V, Finally, the epoch/major/minor/patch methods form yet another I like 'elements' but from the name I would've expected it to return a -- |
From @maukeAm 01.08.2016 um 08:38 schrieb Zefram:
I think that's borderline obfuscated. The biggest WTF in there is "$]": Also, that still counts as reparsing a pretty-printed form. If I wanted @parts = $^V =~ /\d+/g; (which silently fails in 5.6 and 5.8) or @parts = sprintf("%vd", $^V) =~ /\d+/g; (for compatibility). -- |
From zefram@fysh.orgLukas Mai wrote:
It's arcane, yes. But reliable.
To work around [perl #72210].
The sprintf standardises the pattern of digits into what's needed for -zefram |
From @ap* Lukas Mai <plokinom@gmail.com> [2016-07-31 21:48]:
Just use The only annoyance you might have is that you get '5.022001' instead of However, don’t listen to this: * Zefram <zefram@fysh.org> [2016-08-01 08:48]:
… because $] is not a float, and you get in trouble (that the manual $ perl -MDevel::Peek -e 'Dump $]' It’s a string. And always has been. Treat it that way and it will treat @parts = map 0+$_, $] =~ /\A(\d+)\.(\d{3})(\d{3})\z/gaa; But for your stated main concern, I would instead go with printf "use feature ':5.%d';\n", substr $], 2, 3; That’s about as simple as anything gets, aye? Regards, |
From zefram@fysh.orgAristotle Pagaltzis wrote:
No, it's not of that form on every version. On 5.8.0 it's "5.008", -zefram |
From @JohnPeacockOn 08/03/2016 03:49 PM, Lukas Mai wrote:
The version::Internals text originally was part of the main POD and I I actually test the ability to subclass version.pm part of the So here is an example subclass just for you: package vversion; sub vstring { 1; Call it like this: $ perl -I. -Mvversion -MDevel::Peek -E \ SV = PVMG(0x15ee440) at 0x1625c68 That gets you the vstring that you can do anything you want with. In $ perl -MDevel::Peek -E \ SV = PVMG(0x247d920) at 0x24b4c68 Since you seem to be primarily interested in the value of $^V, you can $ perl -MDevel::Peek -E '$v = eval("$^V"); say Dump($v);' All things considered, I think this is not something that absolutely John |
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