Hello. I am new to D and come from some intermediate C/C++ plus some Python programming background. I currently have DMD 2.062 installed on my Kubuntu Raring 64-bit system.

1. Too big binary output?

OK so I wrote my first Hello World program:

#! /usr/bin/rdmd
import std.stdio ;
void main() {
	writeln ( "Namaste Prapancha!" ) ;
}

(so I'm a bit of a Sanskrit geek...) and when I save it as namaste.d, do chmod +x and run ./namaste.d, all is fine and I get the output.

However I am somewhat taken aback to see the file size -- 335KiB for a simple Hello World? The equivalent C/C++ programs compiled with Clang without any -O options produce binaries of less than 10K!

2. No filename freedom?

Next I wanted to go to another example but I like to keep my practice files in order, so I rename namaste.d to 01-namaste.d but I get the error:

$ dmd 01-namaste.d
01-namaste.d: Error: module 01-namaste has non-identifier characters
in filename, use module declaration instead

Huh? Now my program *name* has to be a valid identifier in the language? So I can't have my filename contain a hyphen-minus or start with a digit, and only something like e01_namaste.d is permitted. Why is this?

-- 
Shriramana Sharma ஶ்ரீரமணஶர்மா श्रीरमणशर्मा

On Thu, 30 May 2013 12:13:19 +0100, Shriramana Sharma <samjnaa@gmail.com> wrote:

> Hello. I am new to D and come from some intermediate C/C++ plus some
> Python programming background. I currently have DMD 2.062 installed on
> my Kubuntu Raring 64-bit system.
>
> 1. Too big binary output?
>
> OK so I wrote my first Hello World program:
>
> #! /usr/bin/rdmd
> import std.stdio ;
> void main() {
> 	writeln ( "Namaste Prapancha!" ) ;
> }
>
> (so I'm a bit of a Sanskrit geek...) and when I save it as namaste.d,
> do chmod +x and run ./namaste.d, all is fine and I get the output.
>
> However I am somewhat taken aback to see the file size -- 335KiB for a
> simple Hello World? The equivalent C/C++ programs compiled with Clang
> without any -O options produce binaries of less than 10K!

The D standard library is currently statically linked.  This will change shortly/eventually.

> 2. No filename freedom?
>
> Next I wanted to go to another example but I like to keep my practice
> files in order, so I rename namaste.d to 01-namaste.d but I get the
> error:
>
> $ dmd 01-namaste.d
> 01-namaste.d: Error: module 01-namaste has non-identifier characters
> in filename, use module declaration instead
>
> Huh? Now my program *name* has to be a valid identifier in the
> language? So I can't have my filename contain a hyphen-minus or start
> with a digit, and only something like e01_namaste.d is permitted. Why
> is this?

As the error says "use module declaration instead".  You need to add a "module namaste;" statement to the top of the file 01-namaste.d.  D defaults the module name to the filename, but you can specify it when they differ.

R

-- 
Using Opera's revolutionary email client: http://www.opera.com/mail/

Shriramana Sharma:

> However I am somewhat taken aback to see the file size -- 335KiB for a
> simple Hello World? The equivalent C/C++ programs compiled with Clang
> without any -O options produce binaries of less than 10K!

On Windows32 DMD produces binaries for small programs that are often half the size of binaries generated by similar small C++ programs compiled with G++ (about 300+ against 700+).

D has a garbage collector, runtime type introspection (module info, type info, etc), run-time built-in operations on dynamic arrays (concat, append), associative arrays and some of their operations, a sort (but probably the built-in sort and reverse will be deprecated and later removed), exceptions, and more. All that needs space that's absent in the C++ binary.

-------------------

Regan Heath:

> The D standard library is currently statically linked.  This will change shortly/eventually.

And then you will need the GC somewhere to run it :-) Both static and dynamic linking have their advantages and disadvantages. I think Go has a storng preference for static linking.

Bye,
bearophile

Thanks to all those who kindly replied.

On Thu, May 30, 2013 at 9:57 PM, Regan Heath <regan@netmail.co.nz> wrote:
>
> The D standard library is currently statically linked.  This will change shortly/eventually.

Ah OK -- should have thought of that. So whatever is in libc.so or libstdc++.so doesn't get counted to the size of the C/C++ executables. Likewise we should have a libd.so I suppose. I am all for having shared runtime/stdlib.

-- 
Shriramana Sharma ஶ்ரீரமணஶர்மா श्रीरमणशर्मा