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digitalmars.D.learn - Using std.format required std.string?

reply =?iso-8859-1?Q?Robert_M._M=FCnch?= <robert.muench saphirion.com> writes:
Hi, wondering why this happens:

import std.format;

void ods(T...)(auto ref T args){
  format(args).ptr;
  return;
}

ods("%s   %s", mystring, mystring.ptr);


 Error: undefined identifier format




If I add: "import std.string;" everything compiles and works.

Since the docs of std.format contains all the format specifier 
description etc. I would expect that only including "std.format" should 
be enough.

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster
Mar 15 2015
parent reply "Marc =?UTF-8?B?U2Now7x0eiI=?= <schuetzm gmx.net> writes:
On Sunday, 15 March 2015 at 15:48:34 UTC, Robert M. Münch wrote:

 Hi, wondering why this happens:

 import std.format;

 void ods(T...)(auto ref T args){
  format(args).ptr;
  return;
 }

 ods("%s   %s", mystring, mystring.ptr);


 Error: undefined identifier format




 If I add: "import std.string;" everything compiles and works.

 Since the docs of std.format contains all the format specifier 
 description etc. I would expect that only including 
 "std.format" should be enough.


For whatever reasons, format() used to be defined in std.string. 
Indeed it's unintuitive to have it there, and it also pulls in 
lots of other unrelated things like Unicode tables when you 
import std.string. That's why it was moved into std.format in 
this PR:

https://github.com/D-Programming-Language/phobos/pull/2732

It will be available in 2.067, soon to be released.
Mar 15 2015
parent reply =?iso-8859-1?Q?Robert_M._M=FCnch?= <robert.muench saphirion.com> writes:
 next sibling parent reply =?iso-8859-1?Q?Robert_M._M=FCnch?= <robert.muench saphirion.com>  writes:


On 2015-03-15 17:36:24 +0000, Robert M. Münch said:

 Is there a way to use "version(...)" to have code sections depending on 
 compiler version? Something like:
 
 version(dmd >= 2.067) or version(dmd < 2.067)?


Answerting myself:

static if (__traits(compiles, version_minor < 67))
  import std.string; // format() for versions < 2.0.67
else
  import std.format; // format() for versions >= 2.0.67


-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster



 Mar 15 2015



  parent reply "anonymous" <anonymous example.com>  writes:


On Sunday, 15 March 2015 at 18:03:55 UTC, Robert M. Münch wrote:

 On 2015-03-15 17:36:24 +0000, Robert M. Münch said:

 Is there a way to use "version(...)" to have code sections 
 depending on compiler version? Something like:
 
 version(dmd >= 2.067) or version(dmd < 2.067)?


 Answerting myself:

 static if (__traits(compiles, version_minor < 67))
  import std.string; // format() for versions < 2.0.67
 else
  import std.format; // format() for versions >= 2.0.67


That doesn't do what you want.

You need to `import std.compiler;` for version_minor. Without 
that import, `__traits(compiles, version_minor < 67)` is always 
false, because version_minor is undefined.

And if you add the import, `__traits(compiles, version_minor < 
67)` is always true, no matter the value of version_minor. Use 
`static if(version_minor < 67)` instead.

Also, if you check version_minor, it's probably a good idea to 
check (or static assert) version_major, too.

Finally, there's need for this (yet). `std.string.format` is fine 
with 2.067, too. So unless you're going for (far) future 
compatiblity, you can just do `import std.string;`.



 Mar 15 2015



  parent reply =?iso-8859-1?Q?Robert_M._M=FCnch?= <robert.muench saphirion.com>  writes:


On 2015-03-15 19:16:52 +0000, anonymous said:


 Answerting myself:
 
 static if (__traits(compiles, version_minor < 67))
 import std.string; // format() for versions < 2.0.67
 else
 import std.format; // format() for versions >= 2.0.67


 
 That doesn't do what you want.
 
 You need to `import std.compiler;` for version_minor. Without that 
 import, `__traits(compiles, version_minor < 67)` is always false, 
 because version_minor is undefined.


I have std.compiler imported.


 And if you add the import, `__traits(compiles, version_minor < 67)` is 
 always true, no matter the value of version_minor. Use `static 
 if(version_minor < 67)` instead.


Ah, ok. Got it. so __traits(compiles,...) checks if the code can be 
compiled, that's it.


 Finally, there's need for this (yet). `std.string.format` is fine with 
 2.067, too. So unless you're going for (far) future compatiblity, you 
 can just do `import std.string;`.


I prefer to move things to the "far future compatibility" path ASAP. 
Reduce a lot of maintenance headaches.

Thanks for the feedback.

-- 
Robert M. Münch
http://www.saphirion.com
smarter | better | faster



 Mar 16 2015



  parent  ketmar <ketmar ketmar.no-ip.org>  writes:


On Mon, 16 Mar 2015 12:32:01 +0100, Robert M. M=C3=BCnch wrote:


 I prefer to move things to the "far future compatibility" path ASAP.
 Reduce a lot of maintenance headaches.


then you can check properties, not versions. ;-)

static if (__traits(compiles, {import std.string : format;})) {
  import std.string : format;
} else {
  import std.format : format;
}
=



 Mar 16 2015



prev sibling  parent reply "Mike Parker" <aldacron gmail.com>  writes:


On Sunday, 15 March 2015 at 17:36:24 UTC, Robert M. Münch wrote:


 Ok, good to here. Didn't cath/remember this one.

 Is there a way to use "version(...)" to have code sections 
 depending on compiler version? Something like:

 version(dmd >= 2.067) or version(dmd < 2.067)?


static if( __VERSION__ >= 2.067 ) {
...
}

This works with any D compiler using the DMD frontend.



 Mar 15 2015



  parent  "Mike Parker" <aldacron gmail.com>  writes:


On Monday, 16 March 2015 at 04:31:19 UTC, Mike Parker wrote:

 On Sunday, 15 March 2015 at 17:36:24 UTC, Robert M. Münch wrote:


 Ok, good to here. Didn't cath/remember this one.

 Is there a way to use "version(...)" to have code sections 
 depending on compiler version? Something like:

 version(dmd >= 2.067) or version(dmd < 2.067)?


 static if( __VERSION__ >= 2.067 ) {
 ...
 }


Ugh. 2067, not 2.067.



 Mar 15 2015