Bridging Ousterhout's Dichotomy

Bridging Ousterhout's Dichotomy to hone your prog-fu Andy Grover [email_address] [email_address]

John Ousterhout
“OH-stir-howt”
Creator of Tcl/Tk
Wrote “Scripting: Higher Level Programming for the 21st Century”

The Dichotomy Two kingdoms of languages:
System Languages
Compiled into machine code
Statically typed
Complex data structures & algorithms
Glue/Scripting Languages
Interpreted
Dynamically typed
No complex structures
Runtimes, VM, byte-compiled

I say: Learn One of Each
C and Python
Or Ruby, Ocaml, Haskell, Lisp
Not C++
Are you crazy?
Java if you must
Use Python instead of shell scripting

"I am a big proponent of temporarily changing programming scope every once in a while to reset some assumptions and habits." – John Carmack

The World of C
As close as non-masochists get to the “bare metal”
Everything Unix (esp. old stuff) seems to be written in it
The Linux Kernel
Performance*
Anything that needs to be smallish
“Getting” pointers – a big deal?
Edit, compile, run, crash, repeat inspires ...attention to detail
Like a hand on stove inspires respect for fire

“Code Weight” Weight = running time * size * installed base

C is not for everything Greenspun's 10th Rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.

The World of Python
High-level – dicts and lists, exception handling
Easy, Fun libraries to do everything
Installed modules in src form, just a vi away
Cheeseshop, RubyGems, CPAN
REPL great for learning
Documentation and introspection
Easy text handling & web programming
Don't Repeat Yourself (DRY)

The World of Python
Why is my python process taking 140MB?
I have no idea
Memory is cheap, no worries!
Can I use threads to leverage my many-core CPU?
It will go slower.
I wrote a webapp 6 months ago and now it is obsolete
That was 2 major releases ago
You forgot your TDD unit tests, pal

Comparing C and Python
They both are awesome and they both are terrible
In a complimentary way
Knowing when to use one or the other should be pretty obvious

Benefits of knowing both
Each language learned makes learning an additional language easier
Unless it's Haskell?
Or, look at code in a new language and get the gist straight-off
Perspective
HL informs LL design patterns
LL understanding aids working around HLL's leaky abstractions

Code Co-operation
ctypes – trivial to call C libs from Python
also, SWIG
More developers using HLL/dynamic langs
Language Bindings are key
e.g. DBus in C, most/all clients use via bindings
Git
Could really use a libgit to enable embedded use
Existing wrappers exec cmdline, blech!

Community Co-operation
Practice Noosphere Cultural Exchange
Interact with people from distant cultures

Thanks!

Bridging Ousterhout's Dichotomy

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Bridging Ousterhout’s Dichotomy Presentation Transcript