New monster props "speech_func" and "shout_func"

MonPropsMarker can be used to set "speech_func" and "shout_func" on a
monster, functions which return a string to be used as the monster's
speech/shout message.

4 files changed, 92 insertions, 2 deletions

diff --git a/crawl-ref/docs/develop/levels/advanced.txt b/crawl-ref/docs/develop/levels/advanced.txt
index f9cd653809..f5ffffe725 100644
--- a/crawl-ref/docs/develop/levels/advanced.txt
+++ b/crawl-ref/docs/develop/levels/advanced.txt
@@ -779,6 +779,18 @@ the marker is placed upon. The options currently available are:
 * monster_dies_lua_key: If this property is set to a function, that function
       will be executed upon the monster's death.
 
+* shout_func: If this property is set to a function, that function will be
+      called if the monster shouts, and the string returned by the function
+      will be used as the text of the message.  can return "__NONE" to
+      make the monster not shout, or "__NEXT" to proceed as if there was no
+      speech_func property.
+
+* speech_func: If this property is set to a function, that function will be
+      called if the monster speaks, and the string returned by the function
+      will be used as the text of the message.  can return "__NONE" to
+      make the monster not talk, or "__NEXT" to proceed as if there was no
+      speech_func property.
+
 * speech_key: This will override the initial key searched for in the speech
       database. Setting this to "Edmund", for example, will give the relevant
       monster Edmund's speech.
@@ -792,6 +804,9 @@ An example of MonPropsMarker to replace the description and quote of a monster:
     MARKER: 8 = lua:MonPropsMarker:new {description="What a horrible sight!\n", \
                                         quote='"They were filled with fear!'\n"}
 
+Note that all of the speech related properties will be reset if the monster
+polymorphs.
+
 Lua API reference
 -----------------
 a. The Map.
diff --git a/crawl-ref/source/mon-speak.cc b/crawl-ref/source/mon-speak.cc
index a5424f117b..9d2d8ecc85 100644
--- a/crawl-ref/source/mon-speak.cc
+++ b/crawl-ref/source/mon-speak.cc
@@ -15,8 +15,10 @@
 #include "externs.h"
 
 #include "beam.h"
+#include "cluautil.h"
 #include "database.h"
 #include "debug.h"
+#include "dlua.h"
 #include "ghost.h"
 #include "message.h"
 #include "mon-stuff.h"
@@ -558,8 +560,43 @@ bool mons_speaks(monsters *monster)
     }
     else
     {
+        if (monster->props.exists("speech_func"))
+        {
+#ifdef DEBUG_MONSPEAK
+            mpr("Trying Lua function for monster speech", MSGCH_DIAGNOSTICS);
+#endif
+            lua_stack_cleaner clean(dlua);
+
+            dlua_chunk &chunk = monster->props["speech_func"];
+
+            if (!chunk.load(dlua))
+            {
+                push_monster(dlua, monster);
+                dlua.callfn(NULL, 1, 1);
+                dlua.fnreturns(">s", &msg);
+
+                // __NONE means to be silent, and __NEXT means to try the next
+                // method of getting a speech message.
+                if (msg == "__NONE")
+                {
+#ifdef DEBUG_MONSPEAK
+                    mpr("result: \"__NONE\"!", MSGCH_DIAGNOSTICS);
+#endif
+                    return (false);
+                }
+                if (msg == "__NEXT")
+                    msg.clear();
+            }
+            else
+            {
+                mprf(MSGCH_ERROR,
+                     "Lua speech function for monster '%s' didn't load: %s",
+                     monster->full_name(DESC_PLAIN).c_str(),
+                     dlua.error.c_str());
+            }
+        }
 
-        if (monster->props.exists("speech_key"))
+        if (msg.empty() && monster->props.exists("speech_key"))
         {
             msg = _get_speak_string(prefixes,
                                      monster->props["speech_key"].get_string(),
diff --git a/crawl-ref/source/mon-stuff.cc b/crawl-ref/source/mon-stuff.cc
index 0d4c374ce2..fc109c5aee 100644
--- a/crawl-ref/source/mon-stuff.cc
+++ b/crawl-ref/source/mon-stuff.cc
@@ -2509,6 +2509,12 @@ bool monster_polymorph(monsters *monster, monster_type targetc,
     monster->flags = flags;
     monster->god   = god;
 
+    // Forget various speech/shout Lua functions.
+    monster->props.erase("speech_key");
+    monster->props.erase("speech_prefix");
+    monster->props.erase("speech_func");
+    monster->props.erase("shout_func");
+
     // Keep spells for named monsters, but don't override innate ones
     // for dragons and the like. This means that Sigmund polymorphed
     // into a goblin will still cast spells, but if he ends up as a
diff --git a/crawl-ref/source/shout.cc b/crawl-ref/source/shout.cc
index e4167278ba..d7d21af7a4 100644
--- a/crawl-ref/source/shout.cc
+++ b/crawl-ref/source/shout.cc
@@ -7,8 +7,10 @@
 
 #include "shout.h"
 
+#include "cluautil.h"
 #include "coord.h"
 #include "database.h"
+#include "dlua.h"
 #include "env.h"
 #include "ghost.h"
 #include "jobs.h"
@@ -148,7 +150,37 @@ void handle_monster_shouts(monsters* monster, bool force)
     else
         suffix = " unseen";
 
-    msg = getShoutString(key, suffix);
+    if (monster->props.exists("shout_func"))
+    {
+        lua_stack_cleaner clean(dlua);
+
+        dlua_chunk &chunk = monster->props["shout_func"];
+
+        if (!chunk.load(dlua))
+        {
+            push_monster(dlua, monster);
+            clua_pushcxxstring(dlua, suffix);
+            dlua.callfn(NULL, 2, 1);
+            dlua.fnreturns(">s", &msg);
+
+            // __NONE means to be silent, and __NEXT or __DEFAULT means to try
+            // the next method of getting a shout message.
+            if (msg == "__NONE")
+                return;
+            if (msg == "__DEFAULT" || msg == "__NEXT")
+                msg.clear();
+        }
+        else
+        {
+            mprf(MSGCH_ERROR,
+                 "Lua shout function for monster '%s' didn't load: %s",
+                 monster->full_name(DESC_PLAIN).c_str(),
+                 dlua.error.c_str());
+        }
+    }
+
+    if (msg.empty())
+        msg = getShoutString(key, suffix);
 
     if (msg == "__DEFAULT" || msg == "__NEXT")
         msg = getShoutString(default_msg_key, suffix);