Schemy LISP en DOS, or SLED, is a purely symbolic LISP largely inspired by Scheme. Derived from Kilo LISP but reduced in features like macros and enhanced with others, it runs on DOS and DOS-emulators like DOSBox. SLED features two fundamental data types: Pairs and Atoms.

Atoms include Symbols, Closures, and Special Symbols. Symbols are unique names of up to 16 characters, accepting printable ASCII when escaped. Special symbols manage core functions, such as nil representing an empty list.

Quoting registers symbols as data via the quote special form or the short syntax. Pairs consist of immutable head and tail elements. Lists terminate in nil, while improper lists do not.

Numbers are not native; natural numbers are emulated using tally numeral lists. The system facilitates code evaluation where unquoted data runs as expressions. Bindings link symbols to data via define, and closures result from lambda.

Function application evaluates arguments eagerly and passes them as value lists. SLED serves as a lightweight LISP implementation for retro computing enthusiasts.