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D.gnu - Appender example doesn't work with GDC. GDC bug?

reply BoraxMan <rotflol2 hotmail.com> writes:
The example for appender located here, does not compile with GDC.

https://dlang.org/library/std/array/appender.html

void main()
{
     import std.array;
     import std.stdio: write, writeln, writef, writefln;
     auto w = appender!string;
     // pre-allocate space for at least 10 elements (this avoids 
costly reallocations)
     w.reserve(10);
     assert(w.capacity >= 10);

     w.put('a'); // single elements
     w.put("bc"); // multiple elements

     // use the append syntax
     w ~= 'd';
     w ~= "ef";

     writeln(w[]); // "abcdef"


}

For the line "Writeln(w[]);" GDC reports "error: no [] operator 
overload for type Appender!string".

It works with DMD.

Time to file  a bug report with GCC-GDC?
Dec 27 2019
next sibling parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Saturday, 28 December 2019 at 03:08:48 UTC, BoraxMan wrote:

 For the line "Writeln(w[]);" GDC reports "error: no [] operator 
 overload for type Appender!string".


I think that is just a broken example. Pretty sure it should be 
`w.data` instead of `w[]`.
Dec 27 2019
parent reply rikki cattermole <rikki cattermole.co.nz> writes:
On 28/12/2019 4:30 PM, Adam D. Ruppe wrote:

 On Saturday, 28 December 2019 at 03:08:48 UTC, BoraxMan wrote:

 For the line "Writeln(w[]);" GDC reports "error: no [] operator 
 overload for type Appender!string".


 
 I think that is just a broken example. Pretty sure it should be `w.data` 
 instead of `w[]`.


This was added 5 months ago.

The example is correct.

https://github.com/dlang/phobos/commit/fbbdb721a5424748a485b5b8425e986fff4511a1

FYI: the current version of gdc exists mostly to bootstrap future 
versions of gdc (because of rules surrounding gcc).

You will get instances like this where your gdc build will be severely 
out of date. I would not recommend it for a new(-ish) user as of this 
moment.
Dec 27 2019
parent reply BoraxMan <rotflol2 hotmail.com> writes:
On Saturday, 28 December 2019 at 03:45:04 UTC, rikki cattermole 
wrote:

 On 28/12/2019 4:30 PM, Adam D. Ruppe wrote:

 On Saturday, 28 December 2019 at 03:08:48 UTC, BoraxMan wrote:

 For the line "Writeln(w[]);" GDC reports "error: no [] 
 operator overload for type Appender!string".


 
 I think that is just a broken example. Pretty sure it should 
 be `w.data` instead of `w[]`.


 This was added 5 months ago.

 The example is correct.

 https://github.com/dlang/phobos/commit/fbbdb721a5424748a485b5b8425e986fff4511a1

 FYI: the current version of gdc exists mostly to bootstrap 
 future versions of gdc (because of rules surrounding gcc).

 You will get instances like this where your gdc build will be 
 severely out of date. I would not recommend it for a new(-ish) 
 user as of this moment.


Adams suggestion does work.  Using w.data in place of w[] 
provides the expected result.

The problem is that GDC is part of GCC now, and part of the 
Fedora installation I'm using.  I take it then if I am to start a 
new project where I may end up providing binaries, I should 
eschew using the GDC compiler and use LDC instead?  This kind of 
consideration is not an issue when using C or C++ (at least in 
Linux).  By default the choice is correct.
Dec 28 2019
parent reply Mike Parker <aldacron gmail.com> writes:
On Saturday, 28 December 2019 at 08:25:16 UTC, BoraxMan wrote:


 The problem is that GDC is part of GCC now, and part of the 
 Fedora installation I'm using.  I take it then if I am to start 
 a new project where I may end up providing binaries, I should 
 eschew using the GDC compiler and use LDC instead?  This kind 
 of consideration is not an issue when using C or C++ (at least 
 in Linux).  By default the choice is correct.


If by "correct" you mean the latest and greatest in terms of 
language and library features, then that means DMD. GDC doesn't 
have the sort of manpower behind that gcc and g++ benefit from. 
As I understand it, the version that ships with GCC was further 
hampered by being locked in quite some time ago due to the GCC 
release cycle.

You have three D compilers to choose from. Use the one that meets 
your needs. They all can put out compatible binary output on any 
given platform.
Dec 28 2019
parent BoraxMan <rotflol2 hotmail.com> writes:
On Saturday, 28 December 2019 at 10:41:56 UTC, Mike Parker wrote:

 On Saturday, 28 December 2019 at 08:25:16 UTC, BoraxMan wrote:


 The problem is that GDC is part of GCC now, and part of the 
 Fedora installation I'm using.  I take it then if I am to 
 start a new project where I may end up providing binaries, I 
 should eschew using the GDC compiler and use LDC instead?  
 This kind of consideration is not an issue when using C or C++ 
 (at least in Linux).  By default the choice is correct.


 If by "correct" you mean the latest and greatest in terms of 
 language and library features, then that means DMD. GDC doesn't 
 have the sort of manpower behind that gcc and g++ benefit from. 
 As I understand it, the version that ships with GCC was further 
 hampered by being locked in quite some time ago due to the GCC 
 release cycle.

 You have three D compilers to choose from. Use the one that 
 meets your needs. They all can put out compatible binary output 
 on any given platform.


What I mean by 'correct', is that despite the fact there are 
different C stdlibs out there overall, there is generally one 
which forms the core of a Linux install, and the same is true 
with other unices, as far as I can tell.  For Linux, its glibc, 
regardless of whether I choose GCC or CLANG, the binary links to 
one libc, the same one.  With D though, there is a libphobos for 
each compiler, so if a Linux distro for example was to start 
packaging D software, they would probably want to settle on a 
specific libphobos, which means me using a different compiler 
would mean the end user having to bring in a second libphobos on 
top of the one the distro was designed around.  Then you have 
libraries which may also use libphobos, such as dlangui, which a 
program may link against.

The right compiler is the one which fits best in the "ecosystem" 
of my target audience, not the best for me personally.
Dec 28 2019
prev sibling parent Iain Buclaw <ibuclaw gdcproject.org> writes:
On Saturday, 28 December 2019 at 03:08:48 UTC, BoraxMan wrote:

 The example for appender located here, does not compile with 
 GDC.

 https://dlang.org/library/std/array/appender.html


[---snip---]

 For the line "Writeln(w[]);" GDC reports "error: no [] operator 
 overload for type Appender!string".

 It works with DMD.

 Time to file  a bug report with GCC-GDC?


As others have already said, the example reflects the latest 
release, not the version gdc is based upon.

Luckily, we have been keeping archived docs for quite some time 
now, so you can just switch and read the correct usage examples.

https://docarchives.dlang.io/v2.076.0/phobos/index.html
Dec 28 2019