80 lines
3.1 KiB
Markdown
80 lines
3.1 KiB
Markdown
# Marketplace: Bringing the Network into the Programming Language
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Marketplace is a concurrent language able to express communication,
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enforce isolation, and manage resources. Network-inspired extensions
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to a functional core represent imperative actions as values, giving
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side-effects locality and enabling composition of communicating
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processes.
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Collaborating programs are grouped within task-specific *virtual
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machines* (VMs) to scope their interactions. Conversations between
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programs are multi-party (using a publish/subscribe medium), and
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programs can easily participate in many such conversations at once.
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Marketplace makes *presence* notifications an integral part of
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pub/sub. Programs react to presence and absence notifications that
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report the comings and goings of their peers. Presence serves to
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communicate changes in demand for and supply of services, both within
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a VM and across *nested VM layers*. Programs can give up
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responsibility for maintaining presence information and for scoping
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group communications to their containing VM.
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## Documentation
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A (draft) manual for Marketplace is available
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[here](http://tonyg.github.io/marketplace/).
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## The code
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This repository contains a [Racket](http://racket-lang.org/) package,
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`marketplace`, which includes
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- the implementation of the `#lang marketplace` language, in the
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[top directory](https://github.com/tonyg/marketplace/tree/typeless/).
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- a TCP echo server example, in
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[`examples/echo-paper.rkt`](https://github.com/tonyg/marketplace/tree/typeless/examples/echo-paper.rkt).
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- a TCP chat server example, in
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[`examples/chat-paper.rkt`](https://github.com/tonyg/marketplace/tree/typeless/examples/chat-paper.rkt).
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- Haskell, Erlang and Python implementations of the chat server for comparison, in
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[`examples/chat.hs`](https://github.com/tonyg/marketplace/tree/typeless/examples/chat.hs),
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[`chat.erl`](https://github.com/tonyg/marketplace/tree/typeless/examples/chat.erl),
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and
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[`chat.py`](https://github.com/tonyg/marketplace/tree/typeless/examples/chat.py)
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respectively.
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## Compiling and running the code
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You will need Racket version 6.1.x or later.
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Once you have Racket installed, run
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raco pkg install marketplace
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to install the package from the Racket package repository, or
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raco pkg install --link `pwd`
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from the root directory of the Git checkout to install the package
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from a local snapshot. (Alternatively, `make link` does the same thing.)
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This will make `#lang marketplace` available to programs.
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At this point, you may load and run any of the example `*.rkt` files
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in the
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[`examples/`](https://github.com/tonyg/marketplace/tree/typeless/examples/)
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directory.
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Note that both the echo server and chat server examples do not print
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any output on standard output: instead, they simply start running and
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silently await TCP connections. Once one of the servers is running, in
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a separate window, try `telnet localhost 5999`.
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Note also that both the echo server and the chat server use port 5999,
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so you cannot run both simultaneously.
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## Copyright
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Copyright © Tony Garnock-Jones 2010, 2011, 2012, 2013, 2014.
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