doc/layers.lyx
author Tony Garnock-Jones <tonygarnockjones@gmail.com>
Wed, 16 Jan 2019 17:15:58 +0000
changeset 438 1fe179d53161
parent 0 ea4e1a00864c
permissions -rw-r--r--
Add missing primitive implementation for the plain interpreter.

#LyX 1.3 created this file. For more info see http://www.lyx.org/
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\layout Title

Layering Functionality in ThiNG
\layout Standard

To begin with, we're going to have a simple interpreter of ThiNG code.
 All the advanced features will come in later revisions - we may even bootstrap
 before we've implemented some of them!
\layout Standard

The features we're particularly interested in include:
\layout Itemize

Reflection
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Locations
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Transactions + Exceptions
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Concurrency
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Object Orientation
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Distribution
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Reflection comes in three flavours, for ThiNG: behavioural, structural,
 and lexical.
 Behavioural reflection will be planned for but not actually implemented
 in the first few iterations.
 Structural reflection is a must - generic treatment of objects is required
 for definition of useful tools such as object explorers etc.
 Lexical reflection can wait until we need it for transactions and distribution.
\layout Standard

Locations are important - they are what, in ThiNG, allows access to meta-level
 facilities.
 A computation may stop an entire location and (non-locally) return to its
 creator either a successful result or an exception.
 The first iterations will have support for locations.
\layout Standard

Transactions and exceptions are closely related.
 To begin with, we'll be implementing just exceptions - transactions can
 wait for proper persistence.
 Exceptions will be implemented using the rudimentary meta-level location
 structures we'll require for normal non-local returns.
\layout Standard

Concurrency will be implemented in the first iterations.
 A variant on the continuation-passing transform will be used to compute
 arguments to a message send concurrently.
\layout Standard

Object-orientation will be implemented in the first iterations, although
 not in the way we'll ultimately have it.
 The goal is to have the lookup phase of OO dispatch go via the location
 (= the meta-object), but for the first few iterations we'll hardcode the
 lookup.
 Allowing customisable lookup comes under the category of behavioural reflection.
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Distributed programming will be supported only once we have the rest sufficientl
y pinned down.
 It depends on lexical reflection.
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