From: dagbrown@... (Dave Brown)
Date: 2003-09-16T04:48:29+09:00
Subject: Re: performance and style advice requested

In article <bk4q1b02kb7@enews2.newsguy.com>,
Alex Martelli  <aleaxit@yahoo.com> wrote:
: Ben Giddings wrote:
: 
: > Some style advice:
: > 
: > On Sunday, September 14, 2003, at 12:44  PM, Alex Martelli wrote:
: >> #
: >> # factorial, memoized via an Array
: >> #
: >> $_fact_memo=[1,1,2,6,24,120,720]
: > 
: > Ugh.  This is what really bothers me about python programs.  Ugly
: > underscores.
: 
: Heh -- matter of taste, I guess; what _I_ personally find ugly is
: that leading $, and I left the underscores in to try to ameliorate
: that.  

It just makes it worse.  The $ is ugly for a reason--the use of
global variables is discouraged.  The Ruby Way to do it would be
to put your combinatorial stuff into a module or a class and use
class variables for your memoizing.

: Of course, nothing stops you from moving to a camelCaseish
: $factMemo -- however, not only do I personally find that less
: readable, but I'd also like to leave a hint that the memo is an
: internal implementation detail, not a feature meant for external
: consumption, and I like the convention of a leading _ for that.

I prefer the convention of putting it into a class where it
belongs. :-)

: (Of course, I _could_ wrap up the fact function and its memo in
: a single package in any of various ways, I'm sure, so the "hint"
: aspect is quite secondary).

One of the philosophies of Ruby is that there's no need to drop
hints when you can make things obvious--to both the compiler and
to other programmers.

--Dave