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digitalmars.D.learn - How to import modules?

reply "js.mdnq" <js_adddot+mdng gmail.com> writes:
I created a .d file having a class with the modules tag at the
top and everything public. I put it in a dir and used the -I flag
to include the path. When I import the file I get an undefined
method.

1. Do I need to compile the .d file into a lib or can I just
import the .d and have it included directly. This is easier so I
don't have to recompile when switching compilers.(to gdc)

2. Do I have to mark anything extern in the module?


In C/C++ one can just include the header, which contains code and
it will work. In D, it seems like one has to link in the methods
regardless? (at least when using the `imports <filename>`)

What I'm looking for is to get D to include the module using the
D file directly unless it exists in a lib file. (or at least
compile to a lib file and include it behind the scenes)



I'm also using dot notation.

module/import MyModules.ThisModule; then the path looks like
\Imports\MyModules\ThisModule.d. Not sure if this is the correct
way to organize modules or not.
Dec 03 2012
next sibling parent reply "Mike Parker" <aldacron gmail.com> writes:
On Tuesday, 4 December 2012 at 04:31:40 UTC, js.mdnq wrote:

 I created a .d file having a class with the modules tag at the
 top and everything public. I put it in a dir and used the -I 
 flag
 to include the path. When I import the file I get an undefined
 method.

 1. Do I need to compile the .d file into a lib or can I just
 import the .d and have it included directly. This is easier so I
 don't have to recompile when switching compilers.(to gdc)


The import statement simply tells the compiler which symbols are 
visible. The compiler will not compile imported modules for you. 
Given module foo.d, which imports bar.d, your command line should 
look like this:

dmd -I/path/to/bar bar.d foo.d

Imports tell the compiler which symbols are available, but the 
compiler will not automatically compile imported modules. You'll 
have to do one of four things:

1) specify each source module on the command line so that each 
can be compiled and linked

2) compile each source module individually and then manually link 
the object files yourself

3) compile the imported files into a library and link with it

4) use a build tool like rdmd which parses all the imports makes 
sure they are all compiled.

The only time it's possible to import a module without linking it 
is when it is full of compile time symbols, such as templates 
that are declared there but never instantiated, manifest 
constants, etc...


 2. Do I have to mark anything extern in the module?


No.


 In C/C++ one can just include the header, which contains code 
 and
 it will work. In D, it seems like one has to link in the methods
 regardless? (at least when using the `imports <filename>`)


When the C or C++ source is in the header, this works because the 
preprocessor directly merges the content of the header with the 
source file that includes it. When the source is in a separate 
file and only the interface is in the header, the source files 
need to be compiled and linked. D compilers do not perform any 
sort of substitution or merging like the C preprocessor. Each 
module is compiled into an object file, just as C or C++ source 
files are, and each must be linked into the executable.



 What I'm looking for is to get D to include the module using the
 D file directly unless it exists in a lib file. (or at least
 compile to a lib file and include it behind the scenes)


No D compiler does this. But rdmd, which ships with dmd, does.


 I'm also using dot notation.

 module/import MyModules.ThisModule; then the path looks like
 \Imports\MyModules\ThisModule.d. Not sure if this is the correct
 way to organize modules or not.


That is correct, though the prevailing convention is to use 
lowercase module names.
Dec 03 2012
parent reply "js.mdnq" <js_adddot+mdng gmail.com> writes:
On Tuesday, 4 December 2012 at 07:17:15 UTC, Mike Parker wrote:

 On Tuesday, 4 December 2012 at 04:31:40 UTC, js.mdnq wrote:

 I created a .d file having a class with the modules tag at the
 top and everything public. I put it in a dir and used the -I 
 flag
 to include the path. When I import the file I get an undefined
 method.

 1. Do I need to compile the .d file into a lib or can I just
 import the .d and have it included directly. This is easier so 
 I
 don't have to recompile when switching compilers.(to gdc)


 The import statement simply tells the compiler which symbols 
 are visible. The compiler will not compile imported modules for 
 you. Given module foo.d, which imports bar.d, your command line 
 should look like this:

 dmd -I/path/to/bar bar.d foo.d

 Imports tell the compiler which symbols are available, but the 
 compiler will not automatically compile imported modules. 
 You'll have to do one of four things:

 1) specify each source module on the command line so that each 
 can be compiled and linked

 2) compile each source module individually and then manually 
 link the object files yourself

 3) compile the imported files into a library and link with it

 4) use a build tool like rdmd which parses all the imports 
 makes sure they are all compiled.

 The only time it's possible to import a module without linking 
 it is when it is full of compile time symbols, such as 
 templates that are declared there but never instantiated, 
 manifest constants, etc...


 2. Do I have to mark anything extern in the module?


 No.


 In C/C++ one can just include the header, which contains code 
 and
 it will work. In D, it seems like one has to link in the 
 methods
 regardless? (at least when using the `imports <filename>`)


 When the C or C++ source is in the header, this works because 
 the preprocessor directly merges the content of the header with 
 the source file that includes it. When the source is in a 
 separate file and only the interface is in the header, the 
 source files need to be compiled and linked. D compilers do not 
 perform any sort of substitution or merging like the C 
 preprocessor. Each module is compiled into an object file, just 
 as C or C++ source files are, and each must be linked into the 
 executable.



 What I'm looking for is to get D to include the module using 
 the
 D file directly unless it exists in a lib file. (or at least
 compile to a lib file and include it behind the scenes)


 No D compiler does this. But rdmd, which ships with dmd, does.


 I'm also using dot notation.

 module/import MyModules.ThisModule; then the path looks like
 \Imports\MyModules\ThisModule.d. Not sure if this is the 
 correct
 way to organize modules or not.


 That is correct, though the prevailing convention is to use 
 lowercase module names.


Thanks, I simply imported the modules into the project and I 
guess visual D added them to be compiled in on the command line. 
For now this will work fine.  Maybe eventually I'll write a 
utility that will build up a command line to include all the d 
files in a subdirectory for compilation.
Dec 04 2012
parent "Mike Parker" <aldacron gmail.com> writes:
On Tuesday, 4 December 2012 at 16:53:33 UTC, js.mdnq wrote:

 Thanks, I simply imported the modules into the project and I 
 guess visual D added them to be compiled in on the command 
 line. For now this will work fine.  Maybe eventually I'll write 
 a utility that will build up a command line to include all the 
 d files in a subdirectory for compilation.


I tend to work from the command line and have a simple build 
script that I copy around between projects. You can see a couple 
of different versions of it in my github projects([1] & [2], for 
example) . I generally run 'dmd build' once and from then on out 
just execute 'build' to compile.

[1]https://github.com/aldacron/Derelict3/blob/master/build/build.d
[2]https://github.com/aldacron/t3/blob/master/build.d
Dec 04 2012
prev sibling parent =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
On 12/03/2012 08:31 PM, js.mdnq wrote:

 I created a .d file having a class with the modules tag at the
 top and everything public. I put it in a dir and used the -I flag
 to include the path. When I import the file I get an undefined
 method.


I had written a short chapter about that topic:

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

Ali

-- 
D Programming Language Tutorial: http://ddili.org/ders/d.en/index.html
Dec 04 2012