tangible.start is functional

luprex/core/cpp/world-accessor.cpp

@@ -292,6 +292,128 @@ LuaDefine(tangible_scan, "plane,x,y,radius,omit_nowhere",
     return LS.result();
 }
 
+LuaDefine(tangible_start, "tangible,function,arg1,arg2...",
+    "|Start a thread."
+    "|"
+    "|Every thread is owned by a tangible.  The first argument"
+    "|to 'tangible.start' indicates the tangible that owns"
+    "|the new thread."
+    "|"
+    "|The function can be a lua closure, or it can be a string."
+    "|If it's a string, then the tangible's class will be"
+    "|used to look up the relevant closure."
+    "|"
+    "|The arguments arg1,arg2... will be passed to the"
+    "|function."
+    "|"
+    "|Actor and place aren't passed to the function unless"
+    "|you manually include them in the list arg1, arg2, etc."
+    "|The new thread can, however, use the builtin "
+    "|functions 'tangible.actor' and 'tangible.place' to obtain "
+    "|actor and place.  Actor will be the same actor who "
+    "|called 'tangible.start'.  Place will be the tangible that"
+    "|owns the thread, ie, the tangible passed to 'tangible.start'."
+    "|"
+    "|The new thread doesn't start running instantly:"
+    "|it waits until the current thread is finished.  The"
+    "|current thread must either block (eg, 'wait') or terminate"
+    "|before the new thread can actually begin execution."
+    "|"
+    "|If you start a thread, then start another, then both of"
+    "|the newly-started threads wait until the current thread"
+    "|is finished.  At that point, it is undefined which of the"
+    "|two new threads runs first."
+    "|"
+    "|Threads are owned by tangibles.  If a tangible is"
+    "|deleted, then none of its threads will ever be resumed,"
+    "|for any reason."
+    "|"
+    "|However, if a thread deletes its own place (ie, the tangible"
+    "|that owns the thread), then the thread will be allowed"
+    "|to continue running until it blocks. But from that point"
+    "|forward, the thread will never be resumed for any reason.") {
+
+    int top = lua_gettop(L);
+    if (top < 2) {
+        luaL_error(L, "Not enough arguments to tangible.start");
+        return 0;
+    }
+    int varlen = top - 2;
+
+    World *w = World::fetch_global_pointer(L);
+    w->guard_nopredict(L, "tangible.start");
+
+    LuaVar mt, classtab, plthreads, thread, thinfo;
+    LuaStack LS(L, mt, classtab, plthreads, thread, thinfo);
+    LuaSpecial place(1);
+    LuaSpecial func(2);
+
+    // Confirm that the place is a valid tangible,
+    // and get the tangible ID.
+    w->tangible_get(LS, place);
+    int64_t place_id = LS.tanid(place);
+
+    // Get place's metatable.
+    LS.getmetatable(mt, place);
+    if (!LS.istable(mt)) {
+        luaL_error(L, "invalid tangible passed to tangible.start");
+        return 0;
+    }
+
+    // Get place's threads table.
+    LS.rawget(plthreads, mt, "threads");
+    if (!LS.istable(plthreads)) {
+        luaL_error(L, "invalid tangible passed to tangible.start");
+        return 0;
+    }
+
+    // If the function is actually a function-name,
+    // then convert it to a closure.
+    if (!LS.isfunction(func)) {
+        if (!LS.isstring(func)) {
+            luaL_error(L, "invalid function passed to tangible.start");
+            return 0;
+        }
+        LS.rawget(classtab, mt, "__index");
+        if (!LS.istable(classtab)) {
+            luaL_error(L, "tangible doesn't have a class table in tangible.start");
+            return 0;
+        }
+        LS.rawget(func, classtab, func);
+        if (!LS.isfunction(func)) {
+            luaL_error(L, "tangible doesn't have specified method in tangible.start");
+            return 0;
+        }
+    }
+
+    // Get a thread ID for the new thread
+    int64_t tid = w->alloc_id_predictable();
+
+    // Create a new thread, set up function and arguments.
+    lua_State *CO = LS.newthread(thread);
+    lua_pushvalue(L, func.index());
+    for (int i = 0; i < varlen; i++) {
+        lua_pushvalue(L, i + 3);
+    }
+    lua_xmove(L, CO, varlen + 1);
+    
+    // Create the thread info table.
+    LS.newtable(thinfo);
+    LS.rawset(thinfo, "thread", thread);
+    LS.rawset(thinfo, "actorid", w->lthread_actor_id_);
+    LS.rawset(thinfo, "isnew", true);
+    LS.rawset(thinfo, "useppool", false);
+    LS.rawset(thinfo, "print", false);
+    
+    LS.rawset(plthreads, tid, thinfo);
+    LS.result();
+    
+    // Push the thread's ID into the runnable thread queue.
+    w->schedule(0, tid, place_id);
+    return LS.result();
+}
+
+
 LuaDefine(wait, "nticks",
     "|Wait the specified number of ticks.") {
     World *w = World::fetch_global_pointer(L);