hats vs helms

Something from <Someone>'s list:  some messages have hardcoded references
to "helmet" which sound strange when the character is wearing a hat or cap.
helm_simple_name() is comparable to the existing cloak_simple_name().  It
returns "helm" or "hat" depending upon whether the helmet provides the
same protection that yields the assorted repetitions of "fortunately,
you are wearing a hard helmet".  This choice ends up categorizing elven
leather helm as a hat (which I think is ok given that its undiscovered
description is "leather hat"), contrary to <Someone>'s suggestion that the
distinction be made based on whether the helmet was made of cloth.

     I started on this a year and a half ago but didn't commit it.
Unfortunately I don't remember why and haven't done any significant
additional work now--just recovered from some intervening bit rot and
confirmed that the patch as is seems to be working ok (in the trunk; the
branch side has not been tested).  I suspect that I meant to look for
additional helmet messages which could benefit from conditional headgear
description.  (Those "hard helmet" ones don't need it, although they
should perhaps be moved into a common routine instead of being replicated.)

src/objnam.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)objnam.c	3.4	2004/08/02	*/
+/*	SCCS Id: @(#)objnam.c	3.4	2004/11/11	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -2811,6 +2811,26 @@ struct obj *cloak;
     return "cloak";
 }
 
+/* helm vs hat for messages */
+const char *
+helm_simple_name(helmet)
+struct obj *helmet;
+{
+    /*
+     *	There is some wiggle room here; the result has been chosen
+     *	for consistency with the "protected by hard helmet" messages
+     *	given for various bonks on the head:  headgear that provides
+     *	such protection is a "helm", that which doesn't is a "hat".
+     *
+     *	    elven leather helm / leather hat	-> hat
+     *	    dwarvish iron helm / hard hat	-> helm
+     *	The rest are completely straightforward:
+     *	    fedora, cornuthaum, dunce cap	-> hat
+     *	    all other types of helmets		-> helm
+     */
+    return (helmet && !is_metallic(helmet)) ? "hat" : "helm";
+}
+
 const char *
 mimic_obj_name(mtmp)
 struct monst *mtmp;