"Notepad++ is a free (as in "free speech" and also as in "free beer") source code editor and Notepad replacement that supports several languages. Running in the MS Windows environment, its use is governed by GPL License." citation from

Although you can use almost any text editor (like standard Windows Notepad), we strongly encourage aspiring scripters to use Notepad++. Saying it helps would be an understatement. Follow the link to the Notepad++ web site to download it.

We also recommend downloading plugin files for Notepad++ from the PLUGINS section. These will allow Notepad++ to recognize SPG2 native scripting language SAL.