Function gem_learned

src/shk.c:3197–3231

unlike alter_cost() which operates on a specific item, identifying or forgetting a gem causes all unpaid gems of its type to change value */

/* unlike alter_cost() which operates on a specific item, identifying or
   forgetting a gem causes all unpaid gems of its type to change value */
void
gem_learned(int oindx)
{
    struct obj *obj;
    struct monst *shkp;
    struct bill_x *bp;
    int ct;

    /*
     * Unfortunately, shop bill doesn't have object type included,
     * just obj->oid for each unpaid stack, so we have to go through
     * every bill and every item on that bill and match up against
     * every unpaid stack on the level....
     *
     * Fortunately, there's no need to catch up when changing dungeon
     * levels even if we ID'd or forget some gems while gone from a
     * level.  There won't be any shop bills when arriving; they were
     * either paid before leaving or got treated as robbery and it's
     * too late to adjust pricing.
     */
    for (shkp = next_shkp(fmon, TRUE); shkp;
         shkp = next_shkp(shkp->nmon, TRUE)) {
        ct = ESHK(shkp)->billct;
        bp = ESHK(shkp)->bill_p;
        while (--ct >= 0) {
            obj = find_oid(bp->bo_id);
            if (!obj) /* shouldn't happen */
                continue;
            if ((oindx != STRANGE_OBJECT) ? (obj->otyp == oindx)
                                          : (obj->oclass == GEM_CLASS))
                bp->price = get_cost(obj, shkp);
            ++bp;
        }
    }
}

/* called when an item's value has been enhanced; if it happens to be
   on any shop bill, update that bill to reflect the new higher price