How can I send current line in gedit to terminal?

sudo apt-get install gedit-plugins

This adds more plugins, one of which is an embedded terminal -- Once you've installed, open gedit, go to preferences, and check it in the "plugins" tab.

You can't specifically pipe commands or blocks through, but you can save the file and easily ./test.sh, and it can be helpful for running commands through it as opposed to having another terminal open.

http://www.linuxnov.com/how-to-install-additional-plugins-for-gedit-text-editor/

Hope this helps!

Do you know Autokey?

It wouldn't be hard to make a keyboard shortcut to run the selected line in a shell.

Autokey has many automation features, very useful to have around. And it uses pythons as its scripting language, since you already know it, it will be to get around.