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digitalmars.D.learn - Including a file

reply Vindex <tech.vindex gmail.com> writes:
One of my library modules (for example, libmylib) has the line

`immutable string jsonText = import("thing.json")`


When I try to build a program with this (already installed) 
library I see error

```
ldc2 source/main.d -ofmyprogram -L-l:libmylib.so.0
Error: file "thing.json" cannot be found or not in a path 
specified with -J
```

Is the actual inclusion of the file on import deferred until the 
link step?
Is there a way to avoid this?
I could insert the entire json into the file, but I would hate to 
do that.
Jul 18 2021
next sibling parent reply Adam D Ruppe <destructionator gmail.com> writes:
On Sunday, 18 July 2021 at 17:28:07 UTC, Vindex wrote:

 Error: file "thing.json" cannot be found or not in a path 
 specified with -J


You need to specify the path where it is found with the -J switch 
to the compiler. Like `ldc2 -J. yourfile.d
Jul 18 2021
next sibling parent Vindex <tech.vindex gmail.com> writes:
On Sunday, 18 July 2021 at 17:31:24 UTC, Adam D Ruppe wrote:

 On Sunday, 18 July 2021 at 17:28:07 UTC, Vindex wrote:

 Error: file "thing.json" cannot be found or not in a path 
 specified with -J


 You need to specify the path where it is found with the -J 
 switch to the compiler. Like `ldc2 -J. yourfile.d


I understand it. But it turns out that in order to compile any 
programs with such a library, you need to specify the path to the 
resource directory of this library?
Jul 18 2021
prev sibling parent reply Vindex <tech.vindex gmail.com> writes:
On Sunday, 18 July 2021 at 17:31:24 UTC, Adam D Ruppe wrote:

 On Sunday, 18 July 2021 at 17:28:07 UTC, Vindex wrote:

 Error: file "thing.json" cannot be found or not in a path 
 specified with -J


 You need to specify the path where it is found with the -J 
 switch to the compiler. Like `ldc2 -J. yourfile.d


I already compiled the library itself with -Jres. It turns out 
that this must be done twice? Once when compiling the library, 
the second time when compiling the program.
Jul 18 2021
parent Mathias LANG <geod24 gmail.com> writes:
On Sunday, 18 July 2021 at 17:48:53 UTC, Vindex wrote:

 On Sunday, 18 July 2021 at 17:31:24 UTC, Adam D Ruppe wrote:

 On Sunday, 18 July 2021 at 17:28:07 UTC, Vindex wrote:

 Error: file "thing.json" cannot be found or not in a path 
 specified with -J


 You need to specify the path where it is found with the -J 
 switch to the compiler. Like `ldc2 -J. yourfile.d


 I already compiled the library itself with -Jres. It turns out 
 that this must be done twice? Once when compiling the library, 
 the second time when compiling the program.


Is the inclusion done in a templated function, or in a global ?
If the `import` happens in a function that is not in a root 
module, it won't be necessary to use `-J` when linking the 
program:
```D
module root;

import nonroot;
import std.stdio;

void main ()
{
     writeln(foo());
}

// Some other file:
module nonroot;

string foo ()
{
     string val = import("hello.txt");
     return foo;
}
```

However, if the `import` is in a templated function, it might 
need to be instantiated in the calling module:
```
module root;

import nonroot;
import std.stdio;

void main ()
{
     writeln(foo!"hello.txt"());
}

// Some other file:
module nonroot;

string foo (string path) ()
{
     string val = import(path);
     return foo;
}

```

This will error out because the `foo` function needs to be 
generated inside of the `root` module context:
```
nonroot.d(5): Error: need `-J` switch to import text file 
`hello.txt`
nonroot.d(6): Error: template `foo(string path)()` has no type
root.d(6): Error: template instance `nonroot.foo!"hello.txt"` 
error instantiating
```

An easy way for you to solve this might be to hide the value of 
your JSON file behind a simple function that returns it, so that 
the compiler never analyzes its body. If you use LDC and LTO, I 
doubt it'll make any difference.
Jul 18 2021
prev sibling parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 7/18/21 10:28 AM, Vindex wrote:


 ```
 ldc2 source/main.d -ofmyprogram -L-l:libmylib.so.0
 Error: file "thing.json" cannot be found or not in a path specified 


with -J

 ```

 Is the actual inclusion of the file on import deferred until the link 


step?

I wonder whether it's an ldc thing related to its link-time powers?


 I could insert the entire json into the file, but I would hate to do 


that.

I insert two many-megabytes long tar.gz files in there. :) I unzip and 
untar the files into a cache directory to use at runtime. I just works. 
The zipped version of a json file may be very small.

I my case, the files are gzip'ped during the build stage and I unzip with

   https://dlang.org/phobos/std_zlib.html

Ali
Jul 18 2021