# HG changeset patch
# User jbe
# Date 1495924210 -7200
# Node ID 07e7e218d8df6d9869011060f80f6480f8801f9e
# Parent  a9fea293b2d6830174108d29b0eddc86eb88eba3
Provide "__tostring" meta-method for database error objects

diff -r a9fea293b2d6 -r 07e7e218d8df libraries/mondelefant/mondelefant_native.c
--- a/libraries/mondelefant/mondelefant_native.c	Thu May 25 02:46:23 2017 +0200
+++ b/libraries/mondelefant/mondelefant_native.c	Sun May 28 00:30:10 2017 +0200
@@ -1369,6 +1369,22 @@
   return command_count+1;
 }
 
+// meta-method "__tostring" of error objects:
+static int mondelefant_errorobject_tostring(lua_State *L) {
+  const char *errclass;
+  const char *errmsg;
+  luaL_checktype(L, 1, LUA_TTABLE);
+  lua_settop(L, 1);
+  lua_getfield(L, 1, "code");  // 2
+  lua_getfield(L, 1, "message");  // 3
+  errclass = lua_tostring(L, 2);
+  errmsg = lua_tostring(L, 3);
+  if (!errclass) errclass = "(null)";
+  if (!errmsg) errclass = "(null)";
+  lua_pushfstring(L, "database error of class \"%s\": %s", errclass, errmsg);
+  return 1;
+}
+
 // method "is_kind_of" of error objects:
 static int mondelefant_errorobject_is_kind_of(lua_State *L) {
   const char *errclass;
@@ -1952,6 +1968,7 @@
 
 // registration information for meta-methods of error objects:
 static const struct luaL_Reg mondelefant_errorobject_mt_functions[] = {
+  {"__tostring", mondelefant_errorobject_tostring},
   {NULL, NULL}
 };