I have here a little snippet that just won't run (many issues in here):

void main(string[] args) {
    import std.stdio, std.net.curl, std.algorithm;

    "http://rosettacode.org/wiki/Web_scraping"
         .byLine
         .filter!(q{ a.canFind("D") })
         .each!writeln;
}

Let's start with ldc:

$ ldc --version
LDC - the LLVM D compiler (0.15.1):
      based on DMD v2.066.1 and LLVM 3.5.1
        Default target: x86_64-unknown-linux-gnu
        Host CPU: corei7
      ...

$ ldc test.d
test.d(11): Error: no property 'each' for type 'FilterResult!(unaryFun, SyncLineInputRange)'

Same with gdc:

$ gdc --version
gdc (GCC) 4.9.2
...

$ gdc test.d
test.d:11: error: no property 'each' for type 'FilterResult!(unaryFun, SyncLineInputRange)'

I don't remember if std.algorithm.each existed in v2.066 but I find it hard to believe that it is that recent an addition to phobos.

Well, let's try DMD:

$ dmd --version
DMD64 D Compiler v2.067
...

$ dmd test.d
/usr/lib/libphobos2.a(curl.o): In function `_D3std3net4curl4HTTP21_sharedStaticCtor1500FZv':
(.text._D3std3net4curl4HTTP21_sharedStaticCtor1500FZv+0xf): undefined reference to `curl_version_info'
/usr/lib/libphobos2.a(curl.o): In function `_D3std3net4curl4Curl21_sharedStaticCtor1502FZv':
(.text._D3std3net4curl4Curl21_sharedStaticCtor1502FZv+0xf): undefined reference to `curl_global_init'
/usr/lib/libphobos2.a(curl.o): In function `_D3std3net4curl4Curl21_sharedStaticDtor1503FZv':
(.text._D3std3net4curl4Curl21_sharedStaticDtor1503FZv+0x5): undefined reference to `curl_global_cleanup'
/usr/lib/libphobos2.a(curl_c4c_192.o): In function `_D3std3net4curl4HTTP4Impl6__dtorMFZv':
(.text._D3std3net4curl4HTTP4Impl6__dtorMFZv+0x19): undefined reference to `curl_slist_free_all'
/usr/lib/libphobos2.a(curl_c6e_ea.o): In function `_D3std3net4curl3FTP4Impl6__dtorMFZv':
(.text._D3std3net4curl3FTP4Impl6__dtorMFZv+0x18): undefined reference to `curl_slist_free_all'
/usr/lib/libphobos2.a(curl_c6e_ea.o): In function `_D3std3net4curl3FTP3dupMFZS3std3net4curl3FTP':
(.text._D3std3net4curl3FTP3dupMFZS3std3net4curl3FTP+0xab): undefined reference to `curl_slist_append'
/usr/lib/libphobos2.a(curl_c6e_ea.o): In function `_D3std3net4curl3FTP13clearCommandsMFZv':
(.text._D3std3net4curl3FTP13clearCommandsMFZv+0x20): undefined reference to `curl_slist_free_all'
/usr/lib/libphobos2.a(curl_c6e_ea.o): In function `_D3std3net4curl3FTP10addCommandMFAxaZv':
(.text._D3std3net4curl3FTP10addCommandMFAxaZv+0x67): undefined reference to `curl_slist_append'
/usr/lib/libphobos2.a(curl_c73_432.o): In function `_D3std3net4curl4Curl10initializeMFZv':
(.text._D3std3net4curl4Curl10initializeMFZv+0x47): undefined reference to `curl_easy_init'
/usr/lib/libphobos2.a(curl_c74_149.o): In function `_D3std3net4curl4Curl3dupMFZS3std3net4curl4Curl':
(.text._D3std3net4curl4Curl3dupMFZS3std3net4curl4Curl+0x2b): undefined reference to `curl_easy_duphandle'
/usr/lib/libphobos2.a(curl_c78_37c.o): In function `_D3std3net4curl4Curl8shutdownMFZv':
(.text._D3std3net4curl4Curl8shutdownMFZv+0x1a): undefined reference to `curl_easy_cleanup'
/usr/lib/libphobos2.a(curl_c7a_14c.o): In function `_D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionAxaZv':
(.text._D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionAxaZv+0x5d): undefined reference to `curl_easy_setopt'
/usr/lib/libphobos2.a(curl_c7b_14c.o): In function `_D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionlZv':
(.text._D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionlZv+0x2e): undefined reference to `curl_easy_setopt'
/usr/lib/libphobos2.a(curl_c7c_14c.o): In function `_D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionPvZv':
(.text._D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionPvZv+0x2e): undefined reference to `curl_easy_setopt'
/usr/lib/libphobos2.a(curl_c7d_207.o): In function `_D3std3net4curl4Curl5clearMFE3etc1c4curl10CurlOptionZv':
(.text._D3std3net4curl4Curl5clearMFE3etc1c4curl10CurlOptionZv+0x29): undefined reference to `curl_easy_setopt'
/usr/lib/libphobos2.a(curl_c7e_67c.o): In function `_D3std3net4curl4Curl16clearIfSupportedMFE3etc1c4curl10CurlOptionZv':
(.text._D3std3net4curl4Curl16clearIfSupportedMFE3etc1c4curl10CurlOptionZv+0x29): undefined reference to `curl_easy_setopt'
/usr/lib/libphobos2.a(curl_c7f_2fb.o): In function `_D3std3net4curl4Curl7performMFE3std8typecons41__T4FlagVAyaa12_7468726f774f6e4572726f72Z4FlagZi':
(.text._D3std3net4curl4Curl7performMFE3std8typecons41__T4FlagVAyaa12_7468726f774f6e4572726f72Z4FlagZi+0x22): undefined reference to `curl_easy_perform'
/usr/lib/libphobos2.a(curl_c55_65b.o): In function `_D3std3net4curl4HTTP16addRequestHeaderMFAxaAxaZv':
(.text._D3std3net4curl4HTTP16addRequestHeaderMFAxaAxaZv+0x11b): undefined reference to `curl_slist_append'
/usr/lib/libphobos2.a(curl_c76_4a1.o): In function `_D3std3net4curl4Curl11errorStringMFiZAya':
(.text._D3std3net4curl4Curl11errorStringMFiZAya+0x11): undefined reference to `curl_easy_strerror'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
--- errorlevel 1

Linking error.... It may be interesting there to notice that [1] the foreach version works compiles very well with ldc and gdc (ie: it doesn't seem to be related to a library location problem on my side) and [2] even if no network function is used in the code, simply importing std.net.curl makes it impossible to link when using dmd.

Those may be silly little things, but even if I like D a lot I find these little things tiring (booo, go contribute to fix bug etc....).

On 4/24/15 1:05 PM, cym13 wrote:

> I don't remember if std.algorithm.each existed in v2.066 but I find it
> hard to believe that it is that recent an addition to phobos.

It is: https://issues.dlang.org/show_bug.cgi?id=12409

>
> Well, let's try DMD:
>
> $ dmd --version
> DMD64 D Compiler v2.067
> ....
>
> $ dmd test.d
> /usr/lib/libphobos2.a(curl.o): In function
> `_D3std3net4curl4HTTP21_sharedStaticCtor1500FZv':
> (.text._D3std3net4curl4HTTP21_sharedStaticCtor1500FZv+0xf): undefined
> reference to `curl_version_info'
> /usr/lib/libphobos2.a(curl.o): In function
> `_D3std3net4curl4Curl21_sharedStaticCtor1502FZv':
> (.text._D3std3net4curl4Curl21_sharedStaticCtor1502FZv+0xf): undefined
> reference to `curl_global_init'

[snip]

This is a sign you don't have libcurl available.

> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)

Why not try this switch? use dmd -v and see why curl is not being included in link.

> Those may be silly little things, but even if I like D a lot I find
> these little things tiring (booo, go contribute to fix bug etc....).

These are easily fixed issues. Most people don't run into them. D is usually pretty good when it comes to being able to run out of the box.

-Steve

On Friday, 24 April 2015 at 17:14:53 UTC, Steven Schveighoffer wrote:
> On 4/24/15 1:05 PM, cym13 wrote:
>> $ dmd test.d
>> /usr/lib/libphobos2.a(curl.o): In function
>> `_D3std3net4curl4HTTP21_sharedStaticCtor1500FZv':
>> (.text._D3std3net4curl4HTTP21_sharedStaticCtor1500FZv+0xf): undefined
>> reference to `curl_version_info'
>> /usr/lib/libphobos2.a(curl.o): In function
>> `_D3std3net4curl4Curl21_sharedStaticCtor1502FZv':
>> (.text._D3std3net4curl4Curl21_sharedStaticCtor1502FZv+0xf): undefined
>> reference to `curl_global_init'
>
> [snip]
>
> This is a sign you don't have libcurl available.

You need to link against libcurl explicitly, it doesn't happen automatically:

    dmd -L-lcurl test.d

On 4/24/15 1:26 PM, "Marc =?UTF-8?B?U2Now7x0eiI=?= <schuetzm@gmx.net>" wrote:
> On Friday, 24 April 2015 at 17:14:53 UTC, Steven Schveighoffer wrote:
>> On 4/24/15 1:05 PM, cym13 wrote:
>>> $ dmd test.d
>>> /usr/lib/libphobos2.a(curl.o): In function
>>> `_D3std3net4curl4HTTP21_sharedStaticCtor1500FZv':
>>> (.text._D3std3net4curl4HTTP21_sharedStaticCtor1500FZv+0xf): undefined
>>> reference to `curl_version_info'
>>> /usr/lib/libphobos2.a(curl.o): In function
>>> `_D3std3net4curl4Curl21_sharedStaticCtor1502FZv':
>>> (.text._D3std3net4curl4Curl21_sharedStaticCtor1502FZv+0xf): undefined
>>> reference to `curl_global_init'
>>
>> [snip]
>>
>> This is a sign you don't have libcurl available.
>
> You need to link against libcurl explicitly, it doesn't happen
> automatically:
>
>      dmd -L-lcurl test.d

Really? I thought it did it automatically if you import std.curl?

That is something that needs fixing...

-Steve

On Friday, 24 April 2015 at 17:14:53 UTC, Steven Schveighoffer wrote:
> On 4/24/15 1:05 PM, cym13 wrote:
>
>> I don't remember if std.algorithm.each existed in v2.066 but I find it
>> hard to believe that it is that recent an addition to phobos.
>
> It is: https://issues.dlang.org/show_bug.cgi?id=12409
>

OK. It's always nice to learn something, I didn't see it in the changelog the
first time I checked (on double-check, it is there).

On Friday, 24 April 2015 at 17:26:03 UTC, Marc Schütz wrote:
> On Friday, 24 April 2015 at 17:14:53 UTC, Steven Schveighoffer wrote:
>> On 4/24/15 1:05 PM, cym13 wrote:
>>> $ dmd test.d
>>> /usr/lib/libphobos2.a(curl.o): In function
>>> `_D3std3net4curl4HTTP21_sharedStaticCtor1500FZv':
>>> (.text._D3std3net4curl4HTTP21_sharedStaticCtor1500FZv+0xf): undefined
>>> reference to `curl_version_info'
>>> /usr/lib/libphobos2.a(curl.o): In function
>>> `_D3std3net4curl4Curl21_sharedStaticCtor1502FZv':
>>> (.text._D3std3net4curl4Curl21_sharedStaticCtor1502FZv+0xf): undefined
>>> reference to `curl_global_init'
>>
>> [snip]
>>
>> This is a sign you don't have libcurl available.
>
> You need to link against libcurl explicitly, it doesn't happen automatically:
>
>     dmd -L-lcurl test.d

Nice to have a workarround but it would be much nicer if it did like ldc and gdc that linked didn't need explicit linking...

On 24 April 2015 at 19:34, cym13 via Digitalmars-d <digitalmars-d@puremagic.com> wrote:
> On Friday, 24 April 2015 at 17:26:03 UTC, Marc Schütz wrote:
>>
>> On Friday, 24 April 2015 at 17:14:53 UTC, Steven Schveighoffer wrote:
>>>
>>> On 4/24/15 1:05 PM, cym13 wrote:
>>>>
>>>> $ dmd test.d
>>>> /usr/lib/libphobos2.a(curl.o): In function
>>>> `_D3std3net4curl4HTTP21_sharedStaticCtor1500FZv':
>>>> (.text._D3std3net4curl4HTTP21_sharedStaticCtor1500FZv+0xf): undefined
>>>> reference to `curl_version_info'
>>>> /usr/lib/libphobos2.a(curl.o): In function
>>>> `_D3std3net4curl4Curl21_sharedStaticCtor1502FZv':
>>>> (.text._D3std3net4curl4Curl21_sharedStaticCtor1502FZv+0xf): undefined
>>>> reference to `curl_global_init'
>>>
>>>
>>> [snip]
>>>
>>> This is a sign you don't have libcurl available.
>>
>>
>> You need to link against libcurl explicitly, it doesn't happen automatically:
>>
>>     dmd -L-lcurl test.d
>
>
> Nice to have a workarround but it would be much nicer if it did like ldc and gdc that linked didn't need explicit linking...


You need to explicitly link third party libraries.

On 4/24/15 1:37 PM, Iain Buclaw via Digitalmars-d wrote:

>
>
> You need to explicitly link third party libraries.
>

You shouldn't need to explicitly link anything that comes out of phobos IMO.

-Steve

On Friday, 24 April 2015 at 17:44:32 UTC, Steven Schveighoffer wrote:
> You shouldn't need to explicitly link anything that comes out of phobos IMO.
>
> -Steve

+1, getting pages of linker errors is extremely confusing and intimidating for newcomers to D.

On 04/24/2015 10:26 AM, "Marc =?UTF-8?B?U2Now7x0eiI=?= <schuetzm@gmx.net>" wrote:

> You need to link against libcurl explicitly, it doesn't happen
> automatically:
>
>      dmd -L-lcurl test.d

Another option is to add it to the source:

pragma(lib, "curl");

Then it finds the library on the system and links with it.

Ali