[erlang-questions] Which choice is better? Function or Case

[Thomas Allen]

On 3/10/13 4:27 AM, ok@REDACTED wrote:> I'm trying to think of 
anything nastier for a programmer to
 > do to another programmer than to know something the second
 > programmer needs to know and deliberately choose to conceal
 > it by using ultra-short variable names.  If I have any luck
 > I'll let you know.
 >
 > Seriously, the job of a programmer is to *COMMUNICATE* with
 > other programmers.  I wish I could offer a simple rule for
 > how long to make variable names.  My colleague who refuses
 > to use "i" for a loop index in C++, preferring
 > innerLoopIndex, clearly errs on one side.  Someone who uses
 > T for timestamp, tree, and table in the same module clearly
 > errs on the other.

I agree with this, to a point. Few things irk me as much as

     Ret = fish_bowl:boil(Bowl, timer:minutes(3)),
     %% ...
     Ret.

I've seen many high quality projects that do this, so I cannot criticize 
the technique as some engineering downfall, but never once have I 
encountered a variable of this sort that was not better served by a 
descriptive name. In this case, perhaps `Boiled' is the correct name.

However, this has more to do with variable names that mean nothing in 
context. There's no sense in proscribing short variable names without 
consideration.

Suppose a function that searches a list of `dict()`s which are expected 
to simply store `term()`s for the user, where we cannot infer the type 
or other nature of the value. In that function, I believe that variable 
names such `K' and `V' are entirely suitable, just as `X' and `N' fit 
comfortably in a mathematical function.

What I don't like is variable names like `X', `X1', `X2' in a function 
that is not mathematical at all. Even if a program is full of nothing 
but the simplest functions, their clauses must still be maintained by 
somebody, and there's no sense in deliberately providing vague, short 
variable names simply for the sake of narrower code or less typing.

Of course, there are exceptions to every rule ... "A foolish consistency 
is the hobgoblin of little minds."

Thomas Allen