purple worm digestion

Generally modify the AD_DGST damage type so that:
- players and pets get no AD_DGST nutrition from G_NOCORPSE monsters
- undead no longer convey any nutrition, to either monsters or you-as-monster
  I decided on this based on the age typically assigned to undead corpses.
- digestion conveys 50% or normal nutrition, and takes 25% the time to eat.
- all AD_DGST attacks are now subject to gas spore explosions, including player

src/mhitm.c

@@ -557,6 +557,7 @@ mdamagem(magr, mdef, mattk)
 	int protector =
 	    mattk->aatyp == AT_TENT ? 0 :
 	    mattk->aatyp == AT_KICK ? W_ARMF : W_ARMG;
+	int num;
 
 	if (touch_petrifies(pd) && !resists_ston(magr) &&
 	   (mattk->aatyp != AT_WEAP || !otmp) &&
@@ -595,6 +596,31 @@ mdamagem(magr, mdef, mattk)
 		tmp = mdef->mhp;
 		/* Use up amulet of life saving */
 		if (!!(obj = mlifesaver(mdef))) m_useup(mdef, obj);
+
+		/* Is a corpse for nutrition possible?  It may kill magr */
+		if (!corpse_chance(mdef, magr, TRUE) || magr->mhp < 1)
+		    break;
+
+		/* Pets get nutrition from swallowing monster whole.
+		 * No nutrition from G_NOCORPSE monster, eg, undead.
+		 * DGST monsters don't die from undead corpses
+		 */
+		num = monsndx(mdef->data);
+		if (magr->mtame && !magr->isminion &&
+		    !(mvitals[num].mvflags & G_NOCORPSE)) {
+		    struct obj *virtualcorpse = mksobj(CORPSE, FALSE, FALSE);
+		    int nutrit;
+
+		    virtualcorpse->corpsenm = num;
+		    virtualcorpse->owt = weight(virtualcorpse);
+		    nutrit = dog_nutrition(magr, virtualcorpse);
+		    dealloc_obj(virtualcorpse);
+
+		    /* only 50% nutrition, 25% of normal eating time */
+		    if (magr->meating > 1) magr->meating = (magr->meating+3)/4;
+		    if (nutrit > 1) nutrit /= 2;
+		    EDOG(magr)->hungrytime += nutrit;
+		}
 		break;
 	    case AD_STUN:
 		if (magr->mcan) break;

src/mon.c

@@ -12,7 +12,6 @@
 #include "edog.h"
 #include <ctype.h>
 
-STATIC_DCL boolean FDECL(corpse_chance,(struct monst *));
 STATIC_DCL boolean FDECL(restrap,(struct monst *));
 STATIC_DCL long FDECL(mm_aggression, (struct monst *,struct monst *));
 #ifdef OVL2
@@ -1381,19 +1380,20 @@ register struct monst *mtmp;
 	m_detach(mtmp, mptr);
 }
 
-STATIC_OVL boolean
-corpse_chance(mon)
+/* TRUE if corpse might be dropped, magr may die if mon was swallowed */
+boolean
+corpse_chance(mon, magr, swallowed)
 struct monst *mon;
+struct monst *magr;			/* killer, if swallowed */
+boolean swallowed;			/* digestion */
 {
 	struct permonst *mdat = mon->data;
 	int i, tmp;
 
-
 	if (mdat == &mons[PM_VLAD_THE_IMPALER] || mdat->mlet == S_LICH) {
-		if (cansee(mon->mx, mon->my))
-			pline("%s body crumbles into dust.",
-				s_suffix(Monnam(mon)));
-		return FALSE;
+	    if (cansee(mon->mx, mon->my) && !swallowed)
+		pline("%s body crumbles into dust.", s_suffix(Monnam(mon)));
+	    return FALSE;
 	}
 
 	/* Gas spores always explode upon death */
@@ -1405,6 +1405,28 @@ struct monst *mon;
 	    	else if(mdat->mattk[i].damd)
 	    	    tmp = d((int)mdat->mlevel+1, (int)mdat->mattk[i].damd);
 	    	else tmp = 0;
+		if (swallowed && magr) {
+		    if (magr == &youmonst) {
+			There("is an explosion in your %s!",
+			      body_part(STOMACH));
+			Sprintf(killer_buf, "%s explosion",
+				s_suffix(mdat->mname));
+			losehp(tmp, killer_buf, KILLED_BY_AN);
+		    } else {
+			if (flags.soundok) You_hear("an explosion.");
+			magr->mhp -= tmp;
+			if (magr->mhp < 1) mondied(magr);
+			if (magr->mhp < 1) { /* maybe lifesaved */
+			    if (canspotmon(magr))
+				pline("%s rips open!", Monnam(magr));
+			} else if (canseemon(magr))
+			    pline("%s seems to have indigestion.",
+				  Monnam(magr));
+		    }
+
+		    return FALSE;
+		}
+
 	    	Sprintf(killer_buf, "%s explosion", s_suffix(mdat->mname));
 	    	killer = killer_buf;
 	    	killer_format = KILLED_BY_AN;
@@ -1440,7 +1462,7 @@ register struct monst *mdef;
 	mondead(mdef);
 	if (mdef->mhp > 0) return;	/* lifesaved */
 
-	if (corpse_chance(mdef))
+	if (corpse_chance(mdef, (struct monst *)0, FALSE))
 		(void) make_corpse(mdef);
 }
 
@@ -1708,7 +1730,7 @@ xkilled(mtmp, dest)
 		 * different from whether or not the corpse is "special";
 		 * if we want both, we have to specify it explicitly.
 		 */
-		if (corpse_chance(mtmp))
+		if (corpse_chance(mtmp, (struct monst *)0, FALSE))
 			(void) make_corpse(mtmp);
 	}
 	if(redisp) newsym(x,y);

src/uhitm.c

@@ -1616,10 +1616,16 @@ register struct attack *mattk;
 			    You("hurriedly regurgitate the sizzling in your %s.",
 				body_part(STOMACH));
 			} else {
-			    u.uhunger += mdef->data->cnutrit;
+			    tmp = 1 + (mdef->data->cwt >> 8);
+			    if (corpse_chance(mdef, &youmonst, TRUE) &&
+				!(mvitals[monsndx(mdef->data)].mvflags &
+				  G_NOCORPSE)) {
+				/* nutrition only if there can be a corpse */
+				u.uhunger += (mdef->data->cnutrit+1) / 2;
+			    } else tmp = 0;
 			    Sprintf(msgbuf, "You totally digest %s.",
 					    mon_nam(mdef));
-			    if ((tmp = 3 + (mdef->data->cwt >> 6)) != 0) {
+			    if (tmp != 0) {
 				/* setting afternmv = end_engulf is tempting,
 				 * but will cause problems if the player is
 				 * attacked (which uses his real location) or