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digitalmars.D.learn - How to compile and use an external class

reply Some Guy <me dontspamme.com> writes:
I am busy learning D and I want to be able to use classes now. I am

don't have to think about this kind of thing so I now have no idea
how to compile a program from the command line that uses a class in
another source file.

I have a source file called MyProgram.d which contains the main
program and I have a file called MyClass.d that contains a class
called MyClass. I want to be able to create an instance of MyClass in
the main program but I don't know what to type to compile it the
command line. This is what I have tried so far which doesn't work:

dmd MyProgram.d MyClass.d

Thanks in advance for your help.
Dec 02 2008
next sibling parent reply Lars Kyllingstad <public kyllingen.NOSPAMnet> writes:
Some Guy wrote:

 I am busy learning D and I want to be able to use classes now. I am

 don't have to think about this kind of thing so I now have no idea
 how to compile a program from the command line that uses a class in
 another source file.
 
 I have a source file called MyProgram.d which contains the main
 program and I have a file called MyClass.d that contains a class
 called MyClass. I want to be able to create an instance of MyClass in
 the main program but I don't know what to type to compile it the
 command line. This is what I have tried so far which doesn't work:
 
 dmd MyProgram.d MyClass.d
 
 Thanks in advance for your help.


What error message are you getting? Did you remember to put module and 
import statements in your source files?

MyClass.d:

     module MyClass;

     class MyClass
     {
        ...
     }

MyProgram.d:

     module MyProgram;
     import MyClass;

     void main()
     {
         MyClass m = new MyClass;    // Example
         ...
     }

     ...

(The module statement in MyProgram.d isn't strictly necessary in this 
case, but personally I think it's good form to always declare the name 
of a module.)

-Lars
Dec 02 2008
parent Some Guy <me dontspamme.com> writes:
Thank you for your help. The problem was that I didn't know that you
had to use the import statement to be able to use a class in another
source file.
Dec 02 2008
prev sibling next sibling parent bearophile <bearophileHUGS lycos.com> writes:
Some Guy:

 I am busy learning D and I want to be able to use classes now. I am

 don't have to think about this kind of thing so I now have no idea
 how to compile a program from the command line that uses a class in
 another source file.


The good thing of D is that with just a little push it can become as handy as

modules by itself.
In the meantime you can use a tool like "bud" (or another one named rebuild) to
do that for you. This is bud:
http://www.dsource.org/projects/build/wiki

Bye,
bearophile
Dec 02 2008
prev sibling parent Derek Parnell <derek psych.ward> writes:
On Tue, 2 Dec 2008 09:28:53 +0000 (UTC), Some Guy wrote:


 I am busy learning D and I want to be able to use classes now. I am

 don't have to think about this kind of thing so I now have no idea
 how to compile a program from the command line that uses a class in
 another source file.
 
 I have a source file called MyProgram.d which contains the main
 program and I have a file called MyClass.d that contains a class
 called MyClass. I want to be able to create an instance of MyClass in
 the main program but I don't know what to type to compile it the
 command line. This is what I have tried so far which doesn't work:
 
 dmd MyProgram.d MyClass.d
 
 Thanks in advance for your help.


Seeing that you didn't show us your code, I took the liberty of writing
some example code...

---------- myprogram.d ---------
module myprogram;

// Tell the compiler that this file needs to know
// about what is in the file 'myclass.d'
import myclass;

import std.stdio;    // Need this to use writefln();

void main()
{
    // Create an instance of the class.
    MyClass inst = new MyClass();
    
    // Invoke a method in the instance.    
    writefln("First %s", inst.A_Method());
    
    
    // Create another instance of the class.
    MyClass yai = new MyClass(5);
    
    // Invoke a method in the instance.    
    writefln("Second %s", yai.A_Method());
}
--------- end of file -------------


---------- myclass.d ---------
module myclass;
class MyClass
{
    int SomeAttribute;
    // A class constructor 
    this()
    {
        SomeAttribute = 1;
    }
    
    // Another class constructor 
    this(int InitData)
    {
        SomeAttribute = InitData;
    }
    
    
    // A method
    int A_Method()
    {
        return SomeAttribute;
    }
    
}
--------- end of file -------------


The line to compile these ...

   dmd myprogram myclass

When running the program 'myprogram' you should get ...

c:\>myprogram
First 1
Second 5

-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell
Dec 02 2008