[erlang-questions] I think I wish I could write case Any of whatever -> _ end.

[Richard O'Keefe]

On May 18, 2010, at 12:01 PM, Henning Diedrich wrote:

> But if it was another symbol? Say ~.

No, let's NOT say \sim, a symbol widely used in mathematics and
physics for something that is syntactically a binary relation
and means "sort-of equal, kinda", which is why I want it for
frames, and is used in a variety of programming languages as a
unary operator with negation-related meanings.

But what if it were some other symbol?
Well, WHY a symbol?  What's the difference between @#$%^ and Fred?
The differences are clear:

   + there is an infinite set of variable names, which can be
     chosen to be easy to pronounce and understand, allowing you
     to name many things at the same time

   - a symbol is one thing, probably doesn't have an agreed way
     to say it (is ~ "tilde", "wiggle", "squiggle", "sim",
     "roughly equals", or what) and has no special connexion with
     what it stands for; since there's one of it, it's very hard to
     use in a nested context.

Example:  Common Lisp has
	* the value of the last expression you typed in
	** the old value of *
	*** the old value of **
What happens if you want to refer to the old value of *** ?
Tough luck.  What happens if you miscount and typed ** when
you meant *** ?  Tough luck.  What is the connection between
multiplication and history that makes this memorable?
There isn't one.

(OK: + ++ +++ are the last three forms you typed,
  * ** *** are their (primary) values
  / // /// are the lists of all their values
  - is the form that is being evaluated right now
  How "-" gets to be more recent than "+" is a mystery,
  but at least they managed to blow this up into an
  "arithmetic function = history variable" analogy.
  The consistency is perfect.  < << and <<< do the
  obvious things.  No, wait, there _is_ no obvious
  thing, and if there were, they don't.  Oh well,
  at least there are consistently X, XX, and XXX versions.
  No, wait, there aren't.  -- and --- do not exist.)


Why invent triangular wheels covered in barbed wire and razor blades
when we have nice round rubber ones?