2 files changed, 21 insertions, 4 deletions

diff --git a/src/FbTk/Luamm.cc b/src/FbTk/Luamm.cc
index 80d0926..8824b06 100644
--- a/src/FbTk/Luamm.cc
+++ b/src/FbTk/Luamm.cc
@@ -285,6 +285,16 @@ namespace lua {
         }
     }
 
+    std::string state::checkstring(int narg) throw(lua::check_error, std::bad_alloc)
+    {
+        try {
+            return tostring(narg);
+        }
+        catch(lua::not_string_error &e) {
+            throw_check_error(narg, TSTRING);
+        }
+    }
+
     void *state::checkudata(int narg, const char *tname) throw(lua::check_error, std::bad_alloc)
     {
         checkstack(2);
@@ -299,10 +309,7 @@ namespace lua {
                 pop(2);
             }
         }
-        std::ostringstream str;
-        str << "Invalid argument #" << narg << ": expected " << type_name(TUSERDATA)
-            << ", got " << type_name(type(narg));
-        throw lua::check_error(str.str());
+        throw_check_error(narg, TUSERDATA);
     }
 
     void state::checkstack(int extra) throw(std::bad_alloc)
@@ -478,6 +485,14 @@ namespace lua {
         call(3, 0, 0);
     }
 
+    void state::throw_check_error(int narg, Type expected) throw(lua::check_error)
+    {
+        std::ostringstream str;
+        str << "Invalid argument #" << narg << ": expected " << type_name(expected)
+            << ", got " << type_name(type(narg));
+        throw lua::check_error(str.str());
+    }
+
     std::string state::tostring(int index) throw(lua::not_string_error)
     {
         size_t len;
diff --git a/src/FbTk/Luamm.hh b/src/FbTk/Luamm.hh
index b75fb12..01fb8b1 100644
--- a/src/FbTk/Luamm.hh
+++ b/src/FbTk/Luamm.hh
@@ -161,6 +161,7 @@ namespace lua {
 
         bool safe_compare(lua_CFunction trampoline, int index1, int index2);
         void do_pushclosure(int n);
+        void throw_check_error(int narg, Type expected) throw(lua::check_error) __attribute__((noreturn));
 
         /**
          * The pointed-to value is true if this object still exists. We need this because the
@@ -273,6 +274,7 @@ namespace lua {
         // call() is a protected mode call, we don't allow unprotected calls
         void call(int nargs, int nresults, int errfunc = 0);
         void checkargno(int argno) throw(lua::check_error);
+        std::string checkstring(int narg) throw(lua::check_error, std::bad_alloc);
         void *checkudata(int narg, const char *tname) throw(lua::check_error, std::bad_alloc);
         template<typename T>
         T *checkudata(int narg, const char *tname) throw(lua::check_error, std::bad_alloc) { return static_cast<T *>(checkudata(narg, tname)); }