in reply to Terrible Trouble With Typemaps (XS Question)

(I've never written XS, so take me with a grain of salt.)

When dealing with this kind of thing in C, we'd use a macro #define to make our lives easier. So, I could see something like: 

#define CALL_COUNT_ITEMS_IF( type ) \
if (sv_derived_from(ST(0), type)) { \
      RETVAL=THIS->countItemsIn( \
        *(type *) SvIV((SV*)SvRV(ST(0))) \
      ); \
    }

int
MyClass::countItemsIn (...)
  CODE:
    CALL_COUNT_ITEMS_IF( 'MyList' );
    CALL_COUNT_ITEMS_IF( 'MyHash' );
  OUTPUT:
    RETVAL

[download]

Again, I have no idea if XS provides for a pre-processor or not. Hope this helps!

------
We are the carpenters and bricklayers of the Information Age.

Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

I shouldn't have to say this, but any code, unless otherwise stated, is untested

Replies are listed 'Best First'.
Re^2: Terrible Trouble With Typemaps (XS Question)
by Molt (Chaplain) on Sep 07, 2004 at 14:38 UTC

    Thanks for the help, to be honest I didn't consider the preprocessor since I tend to avoid it as much as possible in the interests of readability.. but in this case it may have a use.

    Just so you know, it will be more a case of:

    int
MyClass::countItemsIn (...)
  CODE:
    if (SV_IS_MYLIST(ST(0))) {
      THIS->countItemsIn (
        CAST_SV_TO_MYLIST(ST(0))
      );
    } elsif (SV_IS_MYHASH(ST(0)) {
      THIS->countItemsIn (
        CAST_SV_TO_MYHASH(ST(0))
      );
    };
  OUTPUT:
   RETVAL

    [download]

    ..where the SV_IS_MYLIST/CAST_SV_TO_MYLIST parts are all macros.

[reply]
[d/l]
      What about the following: 
      CODE:
  if ( MY_SV_IS( ST(0), 'MyList' )) {
    THIS->count_Items_in( MY_CAST_SV( ST(0), 'MyList' )
  } elsif (MY_SV_IS( ST(0), 'MyHash' )) {
    THIS->count_Items_in( MY_CAST_SV( ST(0), 'MyHash' )
  }

      [download]

      This way, you don't have a plethora of macros. Remember, a preprocessor macro is just a direct text substitution. So, you can put text in there, kinda like what I was doing in my first reply.

      ------
      We are the carpenters and bricklayers of the Information Age.

      Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

      I shouldn't have to say this, but any code, unless otherwise stated, is untested

[reply]
[d/l]

        It's got to be a plethora of macros, unfortunately, since the way I convert to MyList could well be very different from the conversion to MyHash.. especially when it comes to handling classes inherited from them.

        Ah well, with a consistant naming strategy there's not too much stuff making the macro namespace unusable.

[reply]

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