I've installed D compiler, and when i try to run a D script with filename without an extension/file type named: program

via: ./program

I'm getting and error:

vaidas@SATELLITE-L855:~/Desktop$ ./program
Error: module `program` is in file './program.d' which cannot be read
import path[0] = .
import path[1] = /snap/dmd/49/bin/../import/druntime
import path[2] = /snap/dmd/49/bin/../import/phobos
Failed: ["/snap/dmd/49/bin/dmd", "-v", "-o-", "./program.d", "-I."]


Now, when I rename my scirpt file : program
To: program.d

and execute it by: ./program.d

I no longer have an error.

Is this an intended behaviour?

On Friday, 1 March 2019 at 09:00:43 UTC, BoQsc wrote:
> I've installed D compiler, and when i try to run a D script with filename without an extension/file type named: program
>
> via: ./program
>
> I'm getting and error:
>
> vaidas@SATELLITE-L855:~/Desktop$ ./program
> Error: module `program` is in file './program.d' which cannot be read
> import path[0] = .
> import path[1] = /snap/dmd/49/bin/../import/druntime
> import path[2] = /snap/dmd/49/bin/../import/phobos
> Failed: ["/snap/dmd/49/bin/dmd", "-v", "-o-", "./program.d", "-I."]
>
>
> Now, when I rename my scirpt file : program
> To: program.d
>
> and execute it by: ./program.d
>
> I no longer have an error.
>
> Is this an intended behaviour?

In such questions it's important to show your shebang since that's what runs your script.

Given your symptoms I guess you're using the following:

#!/bin/env rdmd

And indeed rdmd won't call your script if it doesn't have the proper extension.

Try using this instead:

#!/bin/dmd -run

On Friday, 1 March 2019 at 09:27:33 UTC, Cym13 wrote:
> On Friday, 1 March 2019 at 09:00:43 UTC, BoQsc wrote:
>> I've installed D compiler, and when i try to run a D script with filename without an extension/file type named: program
>>
>> via: ./program
>>
>> I'm getting and error:
>>
>> vaidas@SATELLITE-L855:~/Desktop$ ./program
>> Error: module `program` is in file './program.d' which cannot be read
>> import path[0] = .
>> import path[1] = /snap/dmd/49/bin/../import/druntime
>> import path[2] = /snap/dmd/49/bin/../import/phobos
>> Failed: ["/snap/dmd/49/bin/dmd", "-v", "-o-", "./program.d", "-I."]
>>
>>
>> Now, when I rename my scirpt file : program
>> To: program.d
>>
>> and execute it by: ./program.d
>>
>> I no longer have an error.
>>
>> Is this an intended behaviour?
>
> In such questions it's important to show your shebang since that's what runs your script.
>
> Given your symptoms I guess you're using the following:
>
> #!/bin/env rdmd
>
> And indeed rdmd won't call your script if it doesn't have the proper extension.
>
> Try using this instead:
>
> #!/bin/dmd -run

The shebang I used: #!/usr/bin/env rdmd

I was visiting Dlang Tour and that's where I've got an example of shebang usage, directly from there:
https://tour.dlang.org/tour/en/welcome/run-d-program-locally#/on-the-fly-compilation-with-rdmd

The shebang you suggested actually works perfectly:
#!/bin/dmd -run


"And indeed rdmd won't call your script if it doesn't have the proper extension."

Then why does Dlang Tour includes shebang: #!/usr/bin/env rdmd

Instead of the one you mentioned, that is fool proof. (#!/bin/dmd -run)

Is that an error/mistake in Dlang Tour guide?

On Friday, 1 March 2019 at 11:38:51 UTC, BoQsc wrote:
> "And indeed rdmd won't call your script if it doesn't have the proper extension."
>
> Then why does Dlang Tour includes shebang: #!/usr/bin/env rdmd
>
> Instead of the one you mentioned, that is fool proof. (#!/bin/dmd -run)
>
> Is that an error/mistake in Dlang Tour guide?

You may want to change that too:

#!/bin/dmd -i -run

DMD doesn't automatically compile imported files (at least not until -i came along), rdmd existed to solve that problem... I don't know what value it brings with the -i switch existing.

On Friday, 1 March 2019 at 14:50:45 UTC, Jesse Phillips wrote:
> I don't know what value it brings with the -i switch existing.

Almost none, except that it's twice as slow as DMD because it needs to run DMD twice to learn about all the dependencies.

It's only useful for a few small things now:

- '-e': evaluate d code with all modules automatically imported (though now that there's std.experimental.all this value is gone too)
- makefile deps generation
- shebang line (as arguments can't be part of the shebang line)

(The list is not complete)

On Friday, 1 March 2019 at 16:45:38 UTC, Seb wrote:
> On Friday, 1 March 2019 at 14:50:45 UTC, Jesse Phillips wrote:
>> I don't know what value it brings with the -i switch existing.
>
> Almost none, except that it's twice as slow as DMD because it needs to run DMD twice to learn about all the dependencies.
>
> It's only useful for a few small things now:
>
> - '-e': evaluate d code with all modules automatically imported (though now that there's std.experimental.all this value is gone too)
> - makefile deps generation
> - shebang line (as arguments can't be part of the shebang line)
>
> (The list is not complete)

I forgot one big reason why rdmd is still nice: caching. It does save the generated dependency file list and checks all modification time stamps, s.t. if nothing has changed, it'll run a cached build

On Friday, 1 March 2019 at 11:38:51 UTC, BoQsc wrote:
> On Friday, 1 March 2019 at 09:27:33 UTC, Cym13 wrote:
>> On Friday, 1 March 2019 at 09:00:43 UTC, BoQsc wrote:
>>> [...]
>>
>> In such questions it's important to show your shebang since that's what runs your script.
>>
>> Given your symptoms I guess you're using the following:
>>
>> #!/bin/env rdmd
>>
>> And indeed rdmd won't call your script if it doesn't have the proper extension.
>>
>> Try using this instead:
>>
>> #!/bin/dmd -run
>
> The shebang I used: #!/usr/bin/env rdmd
>
> I was visiting Dlang Tour and that's where I've got an example of shebang usage, directly from there:
> https://tour.dlang.org/tour/en/welcome/run-d-program-locally#/on-the-fly-compilation-with-rdmd
>
> The shebang you suggested actually works perfectly:
> #!/bin/dmd -run
>
>
> "And indeed rdmd won't call your script if it doesn't have the proper extension."
>
> Then why does Dlang Tour includes shebang: #!/usr/bin/env rdmd
>
> Instead of the one you mentioned, that is fool proof. (#!/bin/dmd -run)
>
> Is that an error/mistake in Dlang Tour guide?

Well, because it isn't fool proof either ;-)

It won't work once you start using more files as you would then need the -i flag , but unfortunately most systems don't support more than one shebang argument.

I think it's simply a missing feature of rdmd to accept files without an extension as D programs (though of course the tour could be improved to be more explanatory here too).

On Friday, 1 March 2019 at 14:50:45 UTC, Jesse Phillips wrote:
> On Friday, 1 March 2019 at 11:38:51 UTC, BoQsc wrote:
>> "And indeed rdmd won't call your script if it doesn't have the proper extension."
>>
>> Then why does Dlang Tour includes shebang: #!/usr/bin/env rdmd
>>
>> Instead of the one you mentioned, that is fool proof. (#!/bin/dmd -run)
>>
>> Is that an error/mistake in Dlang Tour guide?
>
> You may want to change that too:
>
> #!/bin/dmd -i -run
>
> DMD doesn't automatically compile imported files (at least not until -i came along), rdmd existed to solve that problem... I don't know what value it brings with the -i switch existing.

All systems I know only accept one argument in shebang so sadly it's not that simple :)

On Friday, 1 March 2019 at 11:38:51 UTC, BoQsc wrote:
> On Friday, 1 March 2019 at 09:27:33 UTC, Cym13 wrote:
>> On Friday, 1 March 2019 at 09:00:43 UTC, BoQsc wrote:
>>> I've installed D compiler, and when i try to run a D script with filename without an extension/file type named: program
>>>
>>> via: ./program
>>>
>>> I'm getting and error:
>>>
>>> vaidas@SATELLITE-L855:~/Desktop$ ./program
>>> Error: module `program` is in file './program.d' which cannot be read
>>> import path[0] = .
>>> import path[1] = /snap/dmd/49/bin/../import/druntime
>>> import path[2] = /snap/dmd/49/bin/../import/phobos
>>> Failed: ["/snap/dmd/49/bin/dmd", "-v", "-o-", "./program.d", "-I."]
>>>
>>>
>>> Now, when I rename my scirpt file : program
>>> To: program.d
>>>
>>> and execute it by: ./program.d
>>>
>>> I no longer have an error.
>>>
>>> Is this an intended behaviour?
>>
>> In such questions it's important to show your shebang since that's what runs your script.
>>
>> Given your symptoms I guess you're using the following:
>>
>> #!/bin/env rdmd
>>
>> And indeed rdmd won't call your script if it doesn't have the proper extension.
>>
>> Try using this instead:
>>
>> #!/bin/dmd -run
>
> The shebang I used: #!/usr/bin/env rdmd
>
> I was visiting Dlang Tour and that's where I've got an example of shebang usage, directly from there:
> https://tour.dlang.org/tour/en/welcome/run-d-program-locally#/on-the-fly-compilation-with-rdmd
>
> The shebang you suggested actually works perfectly:
> #!/bin/dmd -run
>
>
> "And indeed rdmd won't call your script if it doesn't have the proper extension."
>
> Then why does Dlang Tour includes shebang: #!/usr/bin/env rdmd
>
> Instead of the one you mentioned, that is fool proof. (#!/bin/dmd -run)
>
> Is that an error/mistake in Dlang Tour guide?

Frankly using rdmd is closer to being fool-proof, you just haven't hit the corner cases yet :)

I'd either get used to having scripts with a .d extension or make an alias or a quick wrapper in shell and call it "program":

#!/bin/sh
exec rdmd /path/to/program.d "$@"

It's not exactly a mistake, it's just not that important to most people I guess. And as your program grows you're likely to take the habit to compile it and work with the binary directly anyway.