MathGroup Archive 2005

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Types in Mathematica thread

  • To: mathgroup at
  • Subject: [mg62900] Re: Types in Mathematica thread
  • From: "Steven T. Hatton" <hattons at>
  • Date: Thu, 8 Dec 2005 00:04:34 -0500 (EST)
  • References: <dmp9na$hi2$> <dn37bp$35e$>
  • Sender: owner-wri-mathgroup at

Jon Harrop wrote:

>> 7. Downvalues are "default" function structures, or "common" functions,
>> or "built-in function" structures, or "broadest class" functions.
>> Upvalues are "special case" functions, or "user-defined" functions /
>> modifications of built-in or default functions, or "narrow-case"
>> functions, or "context-dependent" functions. (This latter is especially
>> important for AI and for a general understanding of the universe.)
> The fact that Mathematica distinguishes between up- and down-values is
> really incidental (a historical artefact). So I think you're
> over-analysing it.

They certainly have different roles during evaluation. UpValues make a lot
more sense when it comes to operator overloading than does unprotecting and
modifying builtin operators.  This is not only to avoid tinkering with the
implementation and possibly breaking something, it has significant
performance advantages.

The Mathematica Wiki:
Math for Comp Sci
Math for the WWW:

  • Prev by Date: Re: Questions on Apply function
  • Next by Date: UpValues for expressions headed by a string
  • Previous by thread: Re: Re: Types in Mathematica thread
  • Next by thread: Re: Types in Mathematica thread