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digitalmars.D.learn - Real Simple Question?

reply WhatMeWorry <kheaser gmail.com> writes:
This is probably so simple that there's no example anywhere.

Basically, I've got a huge array definition (see below) which I 
reuse over and over again in different projects.

GLfloat[] vertices =
[
     // Positions          // Texture Coords
     -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
      0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
                  .....
              (lots and lots of values)
                  .....

I'd like to place this one array into a separate file and just 
include it with a one line statement in many projects.  I'm 
thinking mixins and/or imports but then if I knew how to do this, 
I wouldn't be asking.

Thanks in advance.
Oct 22 2016
parent reply Jonathan M Davis via Digitalmars-d-learn writes:
On Saturday, October 22, 2016 20:35:27 WhatMeWorry via Digitalmars-d-learn 
wrote:

 This is probably so simple that there's no example anywhere.

 Basically, I've got a huge array definition (see below) which I
 reuse over and over again in different projects.

 GLfloat[] vertices =
 [
      // Positions          // Texture Coords
      -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
       0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
                   .....
               (lots and lots of values)
                   .....

 I'd like to place this one array into a separate file and just
 include it with a one line statement in many projects.  I'm
 thinking mixins and/or imports but then if I knew how to do this,
 I wouldn't be asking.

 Thanks in advance.


Just put it in a separate module and then import it. e.g.

file: mypackage/constants.d
==================
module mypackage.constants;

GLfloat[] vertices =
[
      // Positions          // Texture Coords
      -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
       0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
                   .....
               (lots and lots of values)
                   .....
];
==================

file: main.d
==================
import mypackage.constants;

void main()
{
    auto v = vertices;
}
==================

Probably the key thing to remember is that when you compile your program,
all of the modules that are part of your program rather than a separate
library need to be compiled into it. Simply importing them isn't enough -
though using either rdmd or dub make that easier.

This is the official documentation's page on modules:

http://dlang.org/spec/module.html

This is the chapter from Al's book that covers modules:

http://ddili.org/ders/d.en/modules.html

And you'd almost certainly benefit from simply reading Ali's book as a
whole:

http://ddili.org/ders/d.en/index.html

- Jonathan M Davis
Oct 22 2016
parent reply WhatMeWorry <kheaser gmail.com> writes:
On Saturday, 22 October 2016 at 20:51:14 UTC, Jonathan M Davis 
wrote:

 On Saturday, October 22, 2016 20:35:27 WhatMeWorry via 
 Digitalmars-d-learn wrote:

 [...]


 Just put it in a separate module and then import it. e.g.

 file: mypackage/constants.d
 ==================
 module mypackage.constants;

 GLfloat[] vertices =
 [
       // Positions          // Texture Coords
       -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
        0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
                    .....
                (lots and lots of values)
                    .....
 ];
 ==================

 file: main.d
 ==================
 import mypackage.constants;

 void main()
 {
     auto v = vertices;
 }
 ==================

 Probably the key thing to remember is that when you compile 
 your program, all of the modules that are part of your program 
 rather than a separate library need to be compiled into it. 
 Simply importing them isn't enough - though using either rdmd 
 or dub make that easier.

 This is the official documentation's page on modules:

 http://dlang.org/spec/module.html

 This is the chapter from Al's book that covers modules:

 http://ddili.org/ders/d.en/modules.html

 And you'd almost certainly benefit from simply reading Ali's 
 book as a whole:

 http://ddili.org/ders/d.en/index.html

 - Jonathan M Davis


Ok, but now I'm getting these error in my new 
mypackage/constants.d

..\common\vertex_data.d(5,15): Error: undefined identifier 
'GLfloat'
..\common\vertex_data.d(53,12): Error: undefined identifier 'vec3'

Is there a way to just suck in the text from say a .txt file that 
would not be compiled before inclusion in main.d?
Oct 22 2016
next sibling parent Jonathan M Davis via Digitalmars-d-learn writes:
On Saturday, October 22, 2016 21:34:36 WhatMeWorry via Digitalmars-d-learn 
wrote:

 Ok, but now I'm getting these error in my new
 mypackage/constants.d

 ..\common\vertex_data.d(5,15): Error: undefined identifier
 'GLfloat'
 ..\common\vertex_data.d(53,12): Error: undefined identifier 'vec3'


mypackage/constants.d needs to import the modules for any of the types it's
using, otherwise it doesn't know about them. Modules are not textually
included like header files are in C++ (compilation times would be _way_
worse if they were), so a module only has access to what it imports, and
it's not affected by anything that imports it.


 Is there a way to just suck in the text from say a .txt file that
 would not be compiled before inclusion in main.d?


String imports is a feature, but then you end up with multiple copies of the
array in your program instead of one, and string imports are almost always
the wrong solution.

- Jonathan M Davis
Oct 22 2016
prev sibling next sibling parent tcak <1ltkrs+3wyh1ow7kzn1k sharklasers.com> writes:
On Saturday, 22 October 2016 at 21:34:36 UTC, WhatMeWorry wrote:

 On Saturday, 22 October 2016 at 20:51:14 UTC, Jonathan M Davis 
 wrote:

 [...]


 Ok, but now I'm getting these error in my new 
 mypackage/constants.d

 ..\common\vertex_data.d(5,15): Error: undefined identifier 
 'GLfloat'
 ..\common\vertex_data.d(53,12): Error: undefined identifier 
 'vec3'

 Is there a way to just suck in the text from say a .txt file 
 that would not be compiled before inclusion in main.d?


You could format your array in JSON format, and read it in your 
program. That could be another solution.
Oct 25 2016
prev sibling parent Steven Schveighoffer <schveiguy yahoo.com> writes:
On 10/22/16 5:34 PM, WhatMeWorry wrote:

 On Saturday, 22 October 2016 at 20:51:14 UTC, Jonathan M Davis wrote:

 On Saturday, October 22, 2016 20:35:27 WhatMeWorry via
 Digitalmars-d-learn wrote:

 [...]


 Just put it in a separate module and then import it. e.g.

 file: mypackage/constants.d
 ==================
 module mypackage.constants;

 GLfloat[] vertices =
 [
       // Positions          // Texture Coords
       -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
        0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
                    .....
                (lots and lots of values)
                    .....
 ];




I would make this:

immutable GLfloat[] vertices

If you can do it. This will make it so it's a) accessible from pure 
functions, and b) will not create a separate thread-local copy for each 
thread (if you use threading).


 Ok, but now I'm getting these error in my new mypackage/constants.d

 ...\common\vertex_data.d(5,15): Error: undefined identifier 'GLfloat'
 ...\common\vertex_data.d(53,12): Error: undefined identifier 'vec3'


It's difficult to know why without more code hints, but it appears that 
vertex_data.d needs to import the module that defines these types. Note 
that if you want to have an imported module provide these definitions 
from another module, then you need to public import the module.

So for instance (guessing at your code, since I don't know what you have 
for import statements):

mypackage/my_types.d:

alias GLfloat = float;
alias vec3 = GLfloat[3];

mypackage/constants.d:

public import mypackage.my_types; // this allows importers of 
constants.d to see the types used

GLfloat[] vertices = ...

vertex_data.d:

import mypackage.constants; // pulls in definitions from my_types.d

-Steve
Oct 25 2016