December 27th 2007
I am just getting a talk ready for WYLUG on python.
I sent Dave the following blurb:
Why I love Python:
A talk on the programming language Python, in 3 parts (feel free to
leave in the interludes if you have had enough)
Part 1: Past, Present, Future.
A bit of history and the design of the language, a look at all the
implementations available today, quick tour of built-in and commonly
used modules and future plans.
Part 2: Language overview
A quick tour of the language: builtin types, control structures, using
Part 3: Recent Magic.
Some relatively recent changes that make programming Python even more
Decorators, Generators, List comprehensions, Iterators, Functools and
anything else I can fit in.
Again a whirlwind tour, but you should be impressed and want to read
up on these some more
I have been revisiting some of the Python talks I have watched over the last few years for ideas and will update my ComSci page with links.
I stumbled across some excellent video from RubyConf, particularly the Rubinius one. Rubinius is a ruby VM partially written in Ruby, taking some lessons from Python and Smalltalk. Some of the stuff he bigs up (compiling to bytecode automatically comes to mind) Python has had for ages, but the self hosting aspect is cool (not as cool as PyPy though). Rubinius seems to be doing what Avi Bryant suggested here, learn from the Smalltalk guys and the papers from the Self team that Sun spun off and later bought back to do the hotspot VM for Java. Interesting times for dynamic languages, target the JVM, CLR, self host and generate code in other languages while always writing in the same fun language. I say Ruby envy only because I think the Ruby community does a better job of looking cool and exciting people than the Python one.
Now Haskell joy. After describing working through Yet Another Haskell Tutorial to the 2 friends doing it with me as “not an obviously pleasurable experience” I had a great moment on the train the other day looking at partial application.
(\y -> y*3)
is Haskell for the anonymous function that takes y and multiplies it by 3 (I wish I had LaTeX here to draw the lamda calculus). What I like is that you can also write that as
While this example is trivial, what is happening is interesting. The compiler knows * is an infix operator that takes 2 arguments and that is has been supplied one and “partially applies” the function, making (*3) (a function that takes one argument). One more thing is changing prefix and infix operators around using ( _ ) and ` _ ` , for example:
3 * 5
(*) 3 5
map (*2) [1,2,3]
(*2) `map` [1,2,3]
I hope this second example is clear, map usually is a prefix function that takes a function and a list and returns a list with the result of applying the function to each element (the return value here would be [2,4,6]). This flexibility is neat and is starting to make Haskell a joy to hack in.