#zlisp

#intro

zlisp is a lightweight, Scheme-like Lisp interpreter for the Amstrad CPC series.

#status

zlisp is still pre-release.

#language

zlisp is a simple, garbage-collected Lisp. This describes v0.1 - sufficient functionality to build a functioning REPL, and little else.

#data types

#list

A list is zero or more items that may be lists, or atoms.

(name (Duncan Bayne) address (Melbourne Victoria))

#atoms

An atom is a single datum, which may stand alone (for example, as the result of an arithmetic operation), or be part of a list.

#symbol

Symbols are identifiers, unique to a particular context. They always start with an alphabet character, and are case-sensitive in nature.

bob

#built-in functions

| function | description                                                                                                                                                                          |
|----------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| +        | Adds zero or more numbers to the first number in a list, and returns the total as a number.                                                                                          |
| def      | Associates a symbol with a value; the value may be a list, or any type of atom.                                                                                                      |
| eval     | Evaluates a Lisp list, or atom, and returns either a list, an atom, or nil.                                                                                                          |
| print    | Prints its arguments to the screen.  Returns nil.                                                                                                                                    |
| read     | Reads an argument from the keyboard, echoing it to the screen, ending the read when ENTER is pressed.  Parses the entered value as Lisp, and returns either a list, an atom, or nil. |

#licence

zlisp is licensed under the GNU Lesser Public License 3.0.

#why the LGPL?

The GPL is specifically designed to reduce the usefulness of GPL-licensed code to closed-source, proprietary software. The BSD license (and similar) don't mandate code-sharing if the BSD-licensed code is modified by licensees. The LGPL achieves the best of both worlds: an LGPL-licensed library can be incorporated within closed-source proprietary code, and yet those using an LGPL-licensed library are required to release source code to that library if they change it.