fix issue #510, pull request #519 - vomit effects

Add some vomiting effects:

Trigger divine wrath if hero vomits at an altar's location.  (What
about adding throne and maybe sink special effects too?)

If poly'd into a yellow dragon, breathe (acid) on self.  (I'm not
sure why.)

If on ice and poly'd into an acidic form, melt the ice.  Also,
change melt_ice() to give its message when melting happens at the
hero's location even if hero can't see.

Fixes #519
Fixes #510

doc/fixes37.0

@@ -1,4 +1,4 @@
-NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.595 $ $NHDT-Date: 1626315675 2021/07/15 02:21:15 $
+NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.596 $ $NHDT-Date: 1626390626 2021/07/15 23:10:26 $
 
 General Fixes and Modified Features
 -----------------------------------
@@ -1080,6 +1080,7 @@ menu for what-is command supports /^ and /" to view a list of nearby or whole
 spiders will occasionally spin webs when moving around
 drinking a burning potion of oil will cure being turned into slime
 new bigroom variant, a boulder maze
+vomiting on an altar provokes the deities wrath
 
 
 Platform- and/or Interface-Specific New Features

src/eat.c

@@ -1,4 +1,4 @@
-/* NetHack 3.7	eat.c	$NHDT-Date: 1620548002 2021/05/09 08:13:22 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.243 $ */
+/* NetHack 3.7	eat.c	$NHDT-Date: 1626390626 2021/07/15 23:10:26 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.247 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2012. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -3361,6 +3361,8 @@ floorfood(const char *verb,
 void
 vomit(void) /* A good idea from David Neves */
 {
+    boolean spewed = FALSE;
+
     if (cantvomit(g.youmonst.data)) {
         /* doesn't cure food poisoning; message assumes that we aren't
            dealing with some esoteric body_part() */
@@ -3373,6 +3375,8 @@ vomit(void) /* A good idea from David Neves */
            reaches 0, but only if u.uhs < FAINTING (and !cantvomit()) */
         if (u.uhs >= FAINTING)
             Your("%s heaves convulsively!", body_part(STOMACH));
+        else
+            spewed = TRUE;
     }
 
     /* nomul()/You_can_move_again used to be unconditional, which was
@@ -3383,6 +3387,27 @@ vomit(void) /* A good idea from David Neves */
         g.multi_reason = "vomiting";
         g.nomovemsg = You_can_move_again;
     }
+
+    if (spewed) {
+        struct attack
+            *mattk = attacktype_fordmg(g.youmonst.data, AT_BREA, AD_ACID);
+
+        /* currently, only yellow dragons can breathe acid */
+        if (mattk) {
+            You("breathe acid on yourself..."); /* [why?] */
+            ubreatheu(mattk);
+        }
+        /* vomiting on an altar is, all things considered, rather impolite */
+        if (IS_ALTAR(levl[u.ux][u.uy].typ))
+            altar_wrath(u.ux, u.uy);
+        /* if poly'd into acidic form, stomach acid is stronger than normal */
+        if (acidic(g.youmonst.data)) {
+            /* TODO: if there's a web here, destroy that too (before ice) */
+            if (is_ice(u.ux, u.uy))
+                melt_ice(u.ux, u.uy,
+                         "Your stomach acid melts straight through the ice!");
+        }
+    }
 }
 
 int

src/zap.c

@@ -1,4 +1,4 @@
-/* NetHack 3.7	zap.c	$NHDT-Date: 1620413928 2021/05/07 18:58:48 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.360 $ */
+/* NetHack 3.7	zap.c	$NHDT-Date: 1626390628 2021/07/15 23:10:28 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.369 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2013. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -4457,7 +4457,7 @@ melt_ice(xchar x, xchar y, const char *msg)
     if (Underwater)
         vision_recalc(1);
     newsym(x, y);
-    if (cansee(x, y))
+    if (cansee(x, y) || (x == u.ux && y == u.uy))
         Norep("%s", msg);
     if ((otmp = sobj_at(BOULDER, x, y)) != 0) {
         if (cansee(x, y))