refactor generic lua function caller to Lua ns

library/LuaTools.cpp

@@ -820,6 +820,29 @@ bool DFHack::Lua::SafeCall(color_ostream &out, lua_State *L, int nargs, int nres
     return ok;
 }
 
+bool DFHack::Lua::CallLuaModuleFunction(color_ostream &out, lua_State *L,
+        const char *module_name, const char *fn_name,
+        int nargs, int nres, LuaLambda && args_lambda, LuaLambda && res_lambda,
+        bool perr){
+    if (!lua_checkstack(L, 1 + nargs) ||
+        !Lua::PushModulePublic(out, L, module_name, fn_name)) {
+        if (perr)
+            out.printerr("Failed to load %s Lua code\n", module_name);
+        return false;
+    }
+
+    std::forward<LuaLambda&&>(args_lambda)(L);
+
+    if (!Lua::SafeCall(out, L, nargs, nres, perr)) {
+        if (perr)
+            out.printerr("Failed Lua call to '%s.%s'\n", module_name, fn_name);
+        return false;
+    }
+
+    std::forward<LuaLambda&&>(res_lambda)(L);
+    return true;
+}
+
 // Copied from lcorolib.c, with error handling modifications
 static int resume_helper(lua_State *L, lua_State *co, int narg, int nres)
 {

library/include/LuaTools.h

@@ -24,6 +24,7 @@ distribution.
 
 #pragma once
 
+#include <functional>
 #include <string>
 #include <sstream>
 #include <vector>
@@ -218,6 +219,20 @@ namespace DFHack {namespace Lua {
      */
     DFHACK_EXPORT bool SafeCall(color_ostream &out, lua_State *state, int nargs, int nres, bool perr = true);
 
+    /**
+     * Load named module and function and invoke it via SafeCall. Returns true
+     * on success. If an error is signalled, and perr is true, it is printed and
+     * popped from the stack.
+     */
+    typedef std::function<void(lua_State *)> LuaLambda;
+    static auto DEFAULT_LUA_LAMBDA = [](lua_State *){};
+    DFHACK_EXPORT bool CallLuaModuleFunction(color_ostream &out,
+            lua_State *state, const char *module_name, const char *fn_name,
+            int nargs = 0, int nres = 0,
+            LuaLambda && args_lambda = DEFAULT_LUA_LAMBDA,
+            LuaLambda && res_lambda = DEFAULT_LUA_LAMBDA,
+            bool perr = true);
+
     /**
      * Pops a function from the top of the stack, and pushes a new coroutine.
      */

plugins/overlay.cpp

@@ -102,9 +102,10 @@ namespace DFHack {
 
 static df::coord2d screenSize;
 
-template<typename FA, typename FR>
+static void call_overlay_lua(color_ostream *out, const char *fn_name,
-static void call_overlay_lua(color_ostream *out, const char *fn_name, int nargs,
+        int nargs = 0, int nres = 0,
-                             int nres, FA && args_lambda, FR && res_lambda) {
+        Lua::LuaLambda && args_lambda = Lua::DEFAULT_LUA_LAMBDA,
+        Lua::LuaLambda && res_lambda = Lua::DEFAULT_LUA_LAMBDA) {
     DEBUG(event).print("calling overlay lua function: '%s'\n", fn_name);
 
     CoreSuspender guard;
@@ -115,30 +116,9 @@ static void call_overlay_lua(color_ostream *out, const char *fn_name, int nargs,
     if (!out)
         out = &Core::getInstance().getConsole();
 
-    if (!lua_checkstack(L, 1 + nargs) ||
+    Lua::CallLuaModuleFunction(*out, L, "plugins.overlay", fn_name, nargs, nres,
-        !Lua::PushModulePublic(
+                               std::forward<Lua::LuaLambda&&>(args_lambda),
-            *out, L, "plugins.overlay", fn_name)) {
+                               std::forward<Lua::LuaLambda&&>(res_lambda));
-        out->printerr("Failed to load overlay Lua code\n");
-        return;
-    }
-
-    std::forward<FA&&>(args_lambda)(L);
-
-    if (!Lua::SafeCall(*out, L, nargs, nres))
-        out->printerr("Failed Lua call to '%s'\n", fn_name);
-
-    std::forward<FR&&>(res_lambda)(L);
-}
-
-static auto DEFAULT_LAMBDA = [](lua_State *){};
-template<typename FA>
-static void call_overlay_lua(color_ostream *out, const char *fn_name, int nargs,
-                             int nres, FA && args_lambda) {
-    call_overlay_lua(out, fn_name, nargs, nres, args_lambda, DEFAULT_LAMBDA);
-}
-
-static void call_overlay_lua(color_ostream *out, const char *fn_name) {
-    call_overlay_lua(out, fn_name, 0, 0, DEFAULT_LAMBDA, DEFAULT_LAMBDA);
 }
 
 template<class T>