From: djberg96@... (Daniel Berger)
Date: 2003-11-28T11:32:08+09:00
Subject: rb_hash_aref question: symbols vs strings

Hi all,

I'm writing an extension, and I'm having a little trouble with using a
hash for keyword arguments.  I want to allow a API like this:

Foo.test(
   :bar => "hello",
   'baz' => "world"
)

In the extension to get the key value I do this:

VALUE rbBar = rb_hash_aref(myHash,rb_str_new2("bar"));

If the key "bar" is a string, that works fine.  However, that returns
nil (not a symbol) if "bar" is a symbol.  I know I can do rb_iterate
and I can detect if hash keys are symbols, but I don't know how to
permanately change the key back to a string, i.e. it appears to pass a
copy of the hash, rather than a reference.

// Iterate over hash.  Assume that rb_sym2str() works properly.
static VALUE parse_hash(VALUE array, VALUE class) 
{ 
   VALUE key, tkey, val;

   key = rb_ary_entry(array, 0); // Get key 
   val = rb_ary_entry(array, 1); // Get value 
   
   if(TYPE(key) == T_SYMBOL){ 
      key = rb_sym2str(key); // Convert T_SYMBOL to T_STRING
      printf("Key is now: %s\n",STR2CSTR(key)); // Verify string
      rb_ary_store(array,0,key); // Doesn't work
   }
   
   return array; 
}

Any ideas?

Regards,

Dan