• Chris Williams (20/20) Jun 02 2009 I would like to do something similar to the example at:
• Jarrett Billingsley (25/45) Jun 02 2009 pecified number of items to it. Pseudo-code, but something like this:
• Chris Williams (2/25) Jun 02 2009 Wonderful. Thank you.

Chris Williams <littleratblue yahoo.co.jp> writes:

I would like to do something similar to the example at:

http://www.digitalmars.com/d/1.0/mixin.html

I want to create a class dynamically, but I want to be able to add an
unspecified number of items to it. Pseudo-code, but something like this:

template ClassGen(char[] className, char[][][] classMembers) {
   const char[] ClassGen = "class " ~ className ~ " {";
   for (int i = 0; i < classMembers.length; i++) {
      classGen ~= classMembers[i][0] ~ " " ~ classMembers[i][1] ~ ";"
   }
   classGen ~= "}";
}

mixin(
   ClassGen!(
      "Foo",
      [
         ["int", "bar"],
         ["int", "baz"]
      ]
   )
);

It seems like somehow between templates, mixins, and tuples (tuple arrays?)
that something like this should be possible, but I'm still figuring out the
language.

Jarrett Billingsley <jarrett.billingsley gmail.com> writes:

On Tue, Jun 2, 2009 at 12:03 PM, Chris Williams
<littleratblue yahoo.co.jp> wrote:
 I would like to do something similar to the example at:

 http://www.digitalmars.com/d/1.0/mixin.html

 I want to create a class dynamically, but I want to be able to add an uns=

pecified number of items to it. Pseudo-code, but something like this:
 template ClassGen(char[] className, char[][][] classMembers) {
 =A0 const char[] ClassGen =3D "class " ~ className ~ " {";
 =A0 for (int i =3D 0; i < classMembers.length; i++) {
 =A0 =A0 =A0classGen ~=3D classMembers[i][0] ~ " " ~ classMembers[i][1] ~ =

";"
 =A0 }
 =A0 classGen ~=3D "}";
 }

 mixin(
 =A0 ClassGen!(
 =A0 =A0 =A0"Foo",
 =A0 =A0 =A0[
 =A0 =A0 =A0 =A0 ["int", "bar"],
 =A0 =A0 =A0 =A0 ["int", "baz"]
 =A0 =A0 =A0]
 =A0 )
 );

 It seems like somehow between templates, mixins, and tuples (tuple arrays=

?) that something like this should be possible, but I'm still figuring out =
the language.

You'll be happy to know that your code compiles and works with very
little modification.

char[] ClassGen(char[] className, char[][][] classMembers) {
  char[] ret =3D "class " ~ className ~ " {";
  foreach(member; classMembers)
     ret ~=3D member[0] ~ " " ~ member[1] ~ ";";

  return ret ~ "}";
}

mixin(
  ClassGen(
     "Foo",
     [
        ["int", "bar"],
        ["int", "baz"]
     ]
  )
);

You can't use for loops in templates, so instead you have to use
recursion.  In this case, however, a CTFE function is much terser.

Chris Williams <littleratblue yahoo.co.jp> writes:

Jarrett Billingsley Wrote:
 You'll be happy to know that your code compiles and works with very
 little modification.
 
 char[] ClassGen(char[] className, char[][][] classMembers) {
   char[] ret = "class " ~ className ~ " {";
   foreach(member; classMembers)
      ret ~= member[0] ~ " " ~ member[1] ~ ";";
 
   return ret ~ "}";
 }
 
 mixin(
   ClassGen(
      "Foo",
      [
         ["int", "bar"],
         ["int", "baz"]
      ]
   )
 );
 
 You can't use for loops in templates, so instead you have to use
 recursion.  In this case, however, a CTFE function is much terser.

Wonderful. Thank you.