{{language|Halon |parampass=value |site=http://docs.halon.se/hsl/}} '''HSL''' (Halon Scripting Language) is a domain-specific scripting language originally designed for processing SMTP transaction and email parsing in the Halon SMTP server. A SMTP software for highly dynamic email environment (hosting and telecom) where customer, settings and routing information needs to be handled dynamically (hence the need for a dynamic scripting language). HSL is currently only available in the Halon software engine, but can be used from a command line interface (REPL). The language support basic classes, has first-class functions and modules, and lot of it's features are borrowed from [[PHP]], [[Python]], [[Javascript]] and [[Perl]].