• bearophile <bearophileHUGS lycos.com> Dec 15 2011
• Timon Gehr <timon.gehr gmx.ch> Dec 16 2011
• Sean Kelly <sean invisibleduck.org> Dec 16 2011
• bearophile <bearophileHUGS lycos.com> Dec 16 2011
• Walter Bright <newshound2 digitalmars.com> Dec 16 2011

bearophile <bearophileHUGS lycos.com> writes:

In some cases I use a global variable only from a small small number of
functions, like foo() and main() here:


import std.stdio;
__gshared static int x = 10;
void foo() {
    // uses x
    writeln("foo");
}
void main() {
    auto fptr = &foo;
    fptr();
    auto y = x; // uses x
}


To write more tidy code in some of those situations I'd like a dot syntax to
access static variables of a function:

void foo() {
    __gshared static int x = 10;
    // uses x
    writeln("foo");
}
void main() {
    auto fptr = &foo;
    fptr();
    auto y = foo.x; // uses foo.x
}



Its semantics is similar to just a struct with a static field and a static
opCall:


import std.stdio;
struct Foo {
    __gshared static int x = 10;
    static void opCall() {
        // uses x
        writeln("foo");
    }
}
void main() {
    auto y = Foo.x;
    auto fptr = &Foo.opCall;
    fptr();
}


The advantage of using the dot syntax is that I don't need to modify the
function code and turn it into a struct, with uppercase name, etc.

Bye,
bearophile

Timon Gehr <timon.gehr gmx.ch> writes:

On 12/16/2011 12:48 AM, bearophile wrote:
 In some cases I use a global variable only from a small small number of
functions, like foo() and main() here:


 import std.stdio;
 __gshared static int x = 10;
 void foo() {
      // uses x
      writeln("foo");
 }
 void main() {
      auto fptr =&foo;
      fptr();
      auto y = x; // uses x
 }


 To write more tidy code in some of those situations I'd like a dot syntax to
access static variables of a function:

 void foo() {
      __gshared static int x = 10;
      // uses x
      writeln("foo");
 }
 void main() {
      auto fptr =&foo;
      fptr();
      auto y = foo.x; // uses foo.x
 }



 Its semantics is similar to just a struct with a static field and a static
opCall:


 import std.stdio;
 struct Foo {
      __gshared static int x = 10;
      static void opCall() {
          // uses x
          writeln("foo");
      }
 }
 void main() {
      auto y = Foo.x;
      auto fptr =&Foo.opCall;
      fptr();
 }


 The advantage of using the dot syntax is that I don't need to modify the
function code and turn it into a struct, with uppercase name, etc.

 Bye,
 bearophile


Local variables are not part of the function interface. They are 
implementation details.

Sean Kelly <sean invisibleduck.org> writes:

On Dec 15, 2011, at 3:48 PM, bearophile wrote:

 In some cases I use a global variable only from a small small number =


=20
=20
 import std.stdio;
 __gshared static int x =3D 10;
 void foo() {
    // uses x
    writeln("foo");
 }
 void main() {
    auto fptr =3D &foo;
    fptr();
    auto y =3D x; // uses x
 }
=20
=20
 To write more tidy code in some of those situations I'd like a dot =


=20
 void foo() {
    __gshared static int x =3D 10;
    // uses x
    writeln("foo");
 }
 void main() {
    auto fptr =3D &foo;
    fptr();
    auto y =3D foo.x; // uses foo.x
 }



struct foo {
    __gshared int x =3D 10;
    static void opCall() {
        // uses x
        writeln("foo");
    }
}

void main() {
    auto fptr =3D foo; // sad that the syntax has to change here
    fptr();
    auto y =3D foo.x; // uses foo.x
}=

bearophile <bearophileHUGS lycos.com> writes:

Timon Gehr:

 Local variables are not part of the function interface. They are 
 implementation details.


What I have proposed is just about static variables of functions, not all local
variables.

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

Sean Kelly:

 struct foo {
     __gshared int x = 10;
     static void opCall() {
         // uses x
         writeln("foo");
     }
 }
 
 void main() {
     auto fptr = foo; // sad that the syntax has to change here
     fptr();
     auto y = foo.x; // uses foo.x
 }


I don't know what you were trying to express here (and struct names start with
an upper case in D).

Thank you for your answers,
bearophile

Walter Bright <newshound2 digitalmars.com> writes:

On 12/16/2011 5:37 PM, bearophile wrote:
 Timon Gehr:

 Local variables are not part of the function interface. They are
 implementation details.


 What I have proposed is just about static variables of functions, not all
local variables.


Then you'd have to add marking them with "public" and "private".

It doesn't seem worth the effort.