From: Jim Freeze <jim@...>
Date: 2003-05-06T21:47:58+09:00
Subject: SWIG and Ruby  (Was Re: SWIG on Solaris problem)

On Tuesday,  6 May 2003 at  0:18:24 +0900, Lyle Johnson wrote:
> Jim Freeze wrote:
> 
> OK, this is getting a little trickier. Try this typemap:
> 
>      %module example
> 
>      %typemap(in) (int *pnArgs, String *pString) (int temp, int i) {
>          Check_Type($input, T_ARRAY);
>          temp = RARRAY($input)->len;
>          $1 = &temp;
>          $2 = (String *) malloc(sizeof(String));
>          for (i = 0; i < $1; i++) {
>              $2[i] = StringValuePtr(rb_ary_entry($input, i));
>          }
>      }
> 
>      %typemap(freearg) String *pString {
>          free((void *) pString);
>      }
> 
>      void dbInit(int *pnArgs, String *pString);
 
 Ok, I have been reading the swig docs and I have 
 a few questions. Other than the code above looking
 totally greek to me, the swig manual does its
 best to convince me that I never want to write
 a typemap. So, why do we have to write a typemap
 for something so common as char **? Is it because
 I said that I wanted to call dbInit as:

   dbInit(n, "some string")

 instead of

   dbInit(n, ["some string"])  ?

 Second question, do I need to learn how to write typemaps?

 Third question, what is the $1 and $2 in the above typemap.

 Fourth: Lyle, thanks for all your expert help.

-- 
Jim Freeze
----------
When asked by an anthropologist what the Indians called America before
the white men came, an Indian said simply "Ours."
		-- Vine Deloria, Jr.