Index: config.c
===================================================================
--- config.c	(revision 49334)
+++ config.c	(working copy)
@@ -653,6 +657,8 @@
 					}
 					if (newcat) {
 						move_variables(newcat, *cat);
+						v = ast_variable_new("inherits_", catname);
+						ast_variable_append(*cat, v);
 						ast_category_destroy(newcat);
 						newcat = NULL;
 					}
@@ -665,6 +671,8 @@
 						return -1;
 					}
 					inherit_category(*cat, base);
+					v = ast_variable_new("inherits_", cur);
+					ast_variable_append(*cat, v);
 				}
  			}
  		}
@@ -958,9 +974,13 @@
 	FILE *f;
 	char fn[256];
 	char date[256]="";
+	const char *inherit;
+	const char *pvalue="";
 	time_t t;
 	struct ast_variable *var;
 	struct ast_category *cat;
+	struct ast_category *parent = NULL;
+	
 	struct ast_comment *cmt;
 	int blanklines = 0;
 
@@ -993,28 +1013,61 @@
 			for (cmt = cat->precomments; cmt; cmt=cmt->next)
 			{
 				if (cmt->cmt[0] != ';' || cmt->cmt[1] != '!')
+				{
 					fprintf(f,"%s", cmt->cmt);
+				}
 			}
+			
 			if (!cat->precomments)
 				fprintf(f,"\n");
-			fprintf(f, "[%s]", cat->name);
-			for(cmt = cat->sameline; cmt; cmt=cmt->next)
-			{
+			
+			/* is this an interited user value? */
+			inherit = ast_variable_retrieve(cfg, cat->name, "inherits_");
+			if (inherit) {
+				fprintf(f, "[%s](%s)",cat->name, inherit);
+			} else
+				fprintf(f, "[%s]", cat->name);
+				
+			for(cmt = cat->sameline; cmt; cmt=cmt->next) {
 				fprintf(f,"%s", cmt->cmt);
 			}
 			if (!cat->sameline)
 				fprintf(f,"\n");
 			var = cat->root;
+			
+			/* If this cat has a parent (i.e. if it inherited) only add in things which are different from the parent */
+			if (inherit)
+				parent = ast_category_get(cfg, inherit);
+				
 			while(var) {
-				for (cmt = var->precomments; cmt; cmt=cmt->next)
-				{
-					if (cmt->cmt[0] != ';' || cmt->cmt[1] != '!')
+				for (cmt = var->precomments; cmt; cmt=cmt->next) {
+					if (cmt->cmt[0] != ';' || cmt->cmt[1] != '!') {
 						fprintf(f,"%s", cmt->cmt);
+					}
 				}
-				if (var->sameline) 
-					fprintf(f, "%s %s %s  %s", var->name, (var->object ? "=>" : "="), var->value, var->sameline->cmt);
-				else	
-					fprintf(f, "%s %s %s\n", var->name, (var->object ? "=>" : "="), var->value);
+				if (parent)
+					pvalue = ast_variable_retrieve(cfg, parent->name, var->name);
+
+				if (pvalue) {
+					if (!strcmp(pvalue, var->value)) {
+						/* Same as the parent value - ignore it */
+					} else if (!strcmp(var->name, "inherits_")) {
+						/* Automatically created inheritance marker -- ignore it */
+					} else {
+						if (var->sameline) 
+							fprintf(f, "%s %s %s  %s", var->name, (var->object ? "=>" : "="), var->value, var->sameline->cmt);
+						else	
+							fprintf(f, "%s %s %s\n", var->name, (var->object ? "=>" : "="), var->value);
+					}
+				} else {
+					if (!strcmp(var->name, "inherits_")) {
+						/* Automatically created inheritance marker -- ignore it */
+					} else if (var->sameline) 
+						fprintf(f, "%s %s %s  %s", var->name, (var->object ? "=>" : "="), var->value, var->sameline->cmt);
+					else	
+						fprintf(f, "%s %s %s\n", var->name, (var->object ? "=>" : "="), var->value);
+				}
+				
 				if (var->blanklines) {
 					blanklines = var->blanklines;
 					while (blanklines--)