L# .NET is a dynamic

Dynamic programming language

Dynamic programming language is a term used broadly in computer science to describe a class of high-level programming languages that execute at runtime many common behaviors that other languages might perform during compilation, if at all...

 computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 programming

Computer programming

Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...

 language

Programming language

A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

 intended to be compiled and executed on the Ecma

ECMA

Ecma or ECMA may refer to:* Ecma International, an international standards organization for Information Communication Technology and Consumer Electronics* Engineering College Magazines Associated, a group of student-run engineering-based publications...

-334 and Ecma-335 Common Language Infrastructure

Common Language Infrastructure

The Common Language Infrastructure is an open specification developed by Microsoft and standardized by ISO and ECMA that describes the executable code and runtime environment that form the core of the Microsoft .NET Framework and the free and open source implementations Mono and Portable.NET...

 (CLI). It is a dialect of Lisp, adapted from Paul Graham's proposed Arc

Arc (programming language)

Arc is a dialect of the Lisp programming language now under development by Paul Graham and Robert Morris.- History :In 2001 Paul Graham announced that he was working on a new dialect of Lisp named "Arc"...

 language to exploit the libraries of the .NET Framework

.NET Framework

The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...

, Microsoft

Microsoft

Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

's implementation of the CLI specification.

The language was designed by Rob Blackwell, as was its first implementation. As of 2007, there are no competing implementations.

Rob Blackwell's implementation and documentation of L Sharp is copyleft

Copyleft

Copyleft is a play on the word copyright to describe the practice of using copyright law to offer the right to distribute copies and modified versions of a work and requiring that the same rights be preserved in modified versions of the work...

 free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

.

As of December 2010, it has not been actively maintained since June 2009 (Project Homepage).