[sapug] Erlang, the movie.

Daryl Tester Daryl.Tester at iocane.com.au
Mon Oct 2 02:30:48 CEST 2006

A small movie put together by the Erlang guys to show off the
language's "features".


Maybe it's just me, but the guy giving the bulk of the presentation
reminds me too much of Graham Chapman.

Tangentially related - I've always been fascinated by systems which
are designed to be "long lived runners"; that is, systems that run
for the uptime of the machine that they're on.  Just the mindset
required to achieve this interests me - for example:

*)  The ability to adjust the configuration on the fly.

*)  The ability to modify the software on the fly.

The second point is why I'm so keen to stick a REPL interpreter
into some of the applications I've been working on, and Python's
reference counting helps with this.  Because functions and classes
are first class objects, you can do cunningness like taking a
reference to the function/class, load in the new version of module
and still be able to access the existing code.

e.g. given -


# Module version 1
def x():
    print 'version 1'

>>> import m
>>> x1 = m.x
>>> m.x()
version 1
>>> x1()   # equivalent
version 1

modify m.py:

# Module version 2
def x():
    print 'version 2'

>>> reload (m)
<module 'm' from 'm.py'>
>>> m.x()
version 2
>>> x1()
version 1

It should be possible to set up a "transaction in progress" to
continue being processed "the old way", while new transactions
are processed by the new methods.

Randmon thoughts on a sunny public holiday ...

  Daryl Tester, IOCANE Pty. Ltd.

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