Added socket.connect for compatibility with socket.core <3.0 (fixes #208

).

lualibs/socket.lua

@@ -13,6 +13,22 @@ local socket = require("socket.core")
 
 local _M = socket
 
+-- this is needed in case this library is used when "socket.core" is loaded,
+-- but has an older version of luasocket that does not include `connect`.
+if not socket.connect then
+  socket.connect = function (address, port, laddress, lport)
+    local sock, err = socket.tcp()
+    if not sock then return nil, err end
+    if laddress then
+        local res, err = sock:bind(laddress, lport, -1)
+        if not res then return nil, err end
+    end
+    local res, err = sock:connect(address, port)
+    if not res then return nil, err end
+    return sock
+  end
+end
+
 -----------------------------------------------------------------------------
 -- Exported auxiliar functions
 -----------------------------------------------------------------------------