OK, garbage collection is now working a little bit.

src/c/io/print.c

@@ -209,13 +209,13 @@ struct pso_pointer write( struct pso_pointer frame_pointer ) {
     bool nl_before = c_truep( fetch_arg( frame, 3 ) );
     bool nl_after = c_truep( fetch_arg( frame, 4 ) );
     struct pso_pointer result = object;
-    URL_FILE *output = writep( stream )
+	struct pso2* stream_obj = pointer_to_object( stream );
-        ? pointer_to_object( stream )->payload.stream.stream
-        : file_to_url_file( stdout );
 
     if ( writep( stream ) ) {
         inc_ref( stream );
 
+		URL_FILE *output = stream_obj->payload.stream.stream;
+
         if ( nl_before )
             url_fputwc( L'\n', output );
 

src/c/memory/pso.c

@@ -199,6 +199,10 @@ struct pso_pointer inc_ref( struct pso_pointer pointer ) {
 struct pso_pointer dec_ref( struct pso_pointer pointer ) {
     struct pso2 *object = pointer_to_object( pointer );
 	
+	if (freep(pointer)) {
+		fputws( L"WARNING: SHOULDN'T: Decrementing free object?\n",  stderr);
+	}
+
     if ( !c_nilp( pointer ) && object->header.count > 0
          && object->header.count != MAXREFERENCE ) {
         object->header.count--;
@@ -217,12 +221,11 @@ struct pso_pointer dec_ref( struct pso_pointer pointer ) {
             debug_println( DEBUG_ALLOC );
         }
 #endif
-
+    }
 	if ( object->header.count == 0 ) {
 	    free_object( pointer );
 	    pointer = nil;
 	}
-    }
 
     return pointer;
 }
@@ -259,9 +262,7 @@ struct pso_pointer free_object( struct pso_pointer pointer ) {
         object->payload.words[i] = 0;
     }
 
-    push_freelist( pointer );
+	#ifdef DEBUG		
-
-#ifdef DEBUG		
 		debug_printf( DEBUG_ALLOC, 0, 
 			L"Freeing object of type %3.3s, size class %d, at page %d, offset %d.\n",
 					( ( char * ) ( object->header.tag.bytes.mnemonic ) ),
@@ -270,6 +271,11 @@ struct pso_pointer free_object( struct pso_pointer pointer ) {
 		);
 		
 		allocation_table[size_class][allocation_table_freed]++;
-#endif
+	#endif
+	
+	strncpy((char*) (object->header.tag.bytes.
+	                      mnemonic ), FREETAG, TAGLENGTH );
+
+    push_freelist( pointer );
     return result;
 }

src/c/payloads/exception.c

@@ -59,12 +59,12 @@ struct pso_pointer make_exception( struct pso_pointer frame_pointer ) {
     if ( !c_nilp( result ) && !exceptionp( result ) ) {
         struct pso3 *object = ( struct pso3 * ) pointer_to_object( result );
 
-        object->payload.exception.message = message;
+        object->payload.exception.message = inc_ref(message);
         object->payload.exception.stack =
-            stackp( frame_pointer ) ? frame_pointer : nil;
+            stackp( frame_pointer ) ? inc_ref(frame_pointer) : nil;
         object->payload.exception.meta = ( consp( meta )
-                                           || hashtabp( meta ) ) ? meta : nil;
+                                           || hashtabp( meta ) ) ? inc_ref(meta) : nil;
-        object->payload.exception.cause = exceptionp( cause ) ? cause : nil;
+        object->payload.exception.cause = exceptionp( cause ) ? inc_ref(cause) : nil;
     }
 
     return result;

src/c/payloads/stack.c

@@ -63,6 +63,8 @@ struct pso_pointer make_frame( int arg_count, struct pso_pointer previous,
         new_frame->payload.stack_frame.depth = 0;
     }
 	
+	new_frame->payload.stack_frame.previous = inc_ref( previous);
+
     debug_printf( DEBUG_ALLOC, 1, L"depth is %d...\n",
                   new_frame->payload.stack_frame.depth );
 
@@ -127,7 +129,7 @@ struct pso_pointer make_frame_with_env( int arg_count,
                   arg_count, new_pointer.page, new_pointer.offset );
 #endif
 
-    prev_frame->payload.stack_frame.previous = previous;
+    prev_frame->payload.stack_frame.previous = inc_ref(previous);
 
     if ( stackp( previous ) ) {
         new_frame->payload.stack_frame.depth =
@@ -201,7 +203,7 @@ struct pso_pointer make_frame_with_arglist_and_env( struct pso_pointer
                   arg_count, new_pointer.page, new_pointer.offset );
 #endif
 
-    prev_frame->payload.stack_frame.previous = previous;
+    prev_frame->payload.stack_frame.previous = inc_ref( previous);
 
     if ( stackp( previous ) ) {
         new_frame->payload.stack_frame.depth =
@@ -277,6 +279,12 @@ struct pso_pointer destroy_stack_frame( struct pso_pointer fp,
             dec_ref( frame->payload.stack_frame.arg[i] );
         }
 
+		frame->payload.stack_frame.previous = nil;
+		frame->payload.stack_frame.function = nil;
+		frame->payload.stack_frame.more = nil;
+		frame->payload.stack_frame.locals = nil;
+		frame->payload.stack_frame.env = nil;
+		
         frame->payload.stack_frame.args = 0;
         frame->payload.stack_frame.depth = 0;
     }

src/c/psse.c

@@ -78,6 +78,11 @@ int main( int argc, char *argv[] ) {
     bool show_prompt = false;
     char *infilename = NULL;
 	
+	if ( initialise_io(  ) != 0 ) {
+	     fputs( "Failed to initialise I/O subsystem\n", stderr );
+	     exit( 1 );
+	 }
+
     while ( ( option = getopt( argc, argv, "dhi:ps:v:" ) ) != -1 ) {
         switch ( option ) {
             case 'd':
@@ -109,10 +114,6 @@ int main( int argc, char *argv[] ) {
     }
 
     setlocale( LC_ALL, "" );
-    if ( initialise_io(  ) != 0 ) {
-        fputs( "Failed to initialise I/O subsystem\n", stderr );
-        exit( 1 );
-    }
  
     oblist = initialise_node( 0 );
     debug_print( L"Oblist: ", DEBUG_BOOTSTRAP, 0 );