Hello.

fun.d:
import std.stdio;
void fun() { writeln("Hello"); }

main.d:
import fun;
void main() { fun(); }

$ dmd -oftest fun.d main.d
main.d(2): Error: function expected before (), not module fun of type void

Why can't I use a function of the same name as the module? IIUC import fun imports all the top-level symbols within module fun as well as the symbol fun referring to the module itself. This is just another case of overloading, no? Can't the compiler understand that I am trying to call the function fun.fun() and not the module even when it is followed by ()?

Thanks!

On Tuesday, 17 October 2017 at 06:13:45 UTC, Shriramana Sharma wrote:
> Hello.
>
> fun.d:
> import std.stdio;
> void fun() { writeln("Hello"); }
>
> main.d:
> import fun;
> void main() { fun(); }
>
> $ dmd -oftest fun.d main.d
> main.d(2): Error: function expected before (), not module fun of type void
>
> Why can't I use a function of the same name as the module? IIUC import fun imports all the top-level symbols within module fun as well as the symbol fun referring to the module itself. This is just another case of overloading, no? Can't the compiler understand that I am trying to call the function fun.fun() and not the module even when it is followed by ()?
>
> Thanks!

Compiler made that way so it doesn't guess or assume too much, because later on it will bite you when you don't even expect that, and in some unpredictable place too.

you can always access symbols with fully qualified name, so in this case

void main() { fun.fun(); }

On Tuesday, 17 October 2017 at 07:33:15 UTC, evilrat wrote:
> Compiler made that way so it doesn't guess or assume too much, because later on it will bite you when you don't even expect that, and in some unpredictable place too.

Can you give an example for when it will bite me? It seems very natural to name a module with the name of the main class or function implemented in that module. Python modules like datetime follow this. What is the problem?

Especially in D the compiler is all-powerful and knows when to resolve to which symbol. If D compiler can resolve between multiple overloads in other cases, why not resolve here?

You can:

import fun : fun;

int main(string[] args)
{
    fun();
    return 0;
}

On Tue, Oct 17, 2017 at 10:08 AM, Shriramana Sharma via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com> wrote:

> On Tuesday, 17 October 2017 at 07:33:15 UTC, evilrat wrote:
>
>> Compiler made that way so it doesn't guess or assume too much, because later on it will bite you when you don't even expect that, and in some unpredictable place too.
>>
>
> Can you give an example for when it will bite me? It seems very natural to name a module with the name of the main class or function implemented in that module. Python modules like datetime follow this. What is the problem?
>
> Especially in D the compiler is all-powerful and knows when to resolve to which symbol. If D compiler can resolve between multiple overloads in other cases, why not resolve here?
>

On Tuesday, 17 October 2017 at 08:26:12 UTC, Daniel Kozak wrote:
> You can:
> import fun : fun;

Yes I found this but it is unnecessarily verbose.

At the same time I also find that it is possible to declare a struct or class with the same name as module:

str.d:
struct str { int a; }

strmain.d:
import str;
void main() { str var; var.a = 2; }

cla.d:
class cla { int a; }

clamain.d:
import cla;
void main() { auto var = new cla; var.a = 2; }

$ dmd -ofstr str.d strmain.d
$ dmd -ofcla cla.d clamain.d

Problem only with function. If there can be a class or struct then what's the problem with function? Doesn't look like any of the problems which "will come and bite you later" in this case…

Have reported https://issues.dlang.org/show_bug.cgi?id=17907

On 10/17/17 2:13 AM, Shriramana Sharma wrote:
> Hello.
> 
> fun.d:
> import std.stdio;
> void fun() { writeln("Hello"); }
> 
> main.d:
> import fun;
> void main() { fun(); }
> 
> $ dmd -oftest fun.d main.d
> main.d(2): Error: function expected before (), not module fun of type void
> 
> Why can't I use a function of the same name as the module? IIUC import fun imports all the top-level symbols within module fun as well as the symbol fun referring to the module itself. This is just another case of overloading, no? Can't the compiler understand that I am trying to call the function fun.fun() and not the module even when it is followed by ()?

I know you have filed a report, and probably it should be considered (it surprises me that types work but functions don't, they are all symbols).

But just as reference, the reason it doesn't come up much is because most modules are within a package, which means you never have top level modules.

But it probably doesn't make a lot of sense to create a package if your library only has one module. It's just not very common.

-Steve