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Title: Greenspun - A Lisp Extension Library for Go
Proposer: Eleanor McHugh
Type: Case-Study
Duration: 90 mins
Description:
Greenspun [http://github.com/feyeleanor/greenspun] is a lightweight implementation of Lisp written in Go and intended for use as an application extension language. It features a byte code virtual machine based on the SECD architecture and a DSL for performing Lisp-like data manipulations in core application logic.

During the course of this session we'll explore three main topics through the design and implementation of the Greenspun system.

Firstly we'll take a deep dive into the Go programming language, with particular emphasis on its type system and compositional approach to object orientation as well as it's first-class support for concurrency. We'll introduce Go's testing and benchmarking system as an essential tool for day-to-day development.

Next we'll look at the implementation of a traditional SECD virtual machine in Go, a popular model for executing programs in functional languages. The core of the SECD architecture is a set of four registers (Stack, Environment, Control and Dump) referencing singly-linked lists and a byte code with ten instructions which we'll study in detail along with the compiler for translating Lisp s-expressions into byte code.

We'll conclude the session by exploring modifications to the SECD architecture which support Go's user-defined types, concurrent execution, tail call elimination, wrapping system calls and general performance enhancements.

By the end of the session attendees should be comfortable reading Go source code, have a basic feel for developing with the language and the necessary background to write their own Lisp implementation.