Re: terminology

From: Marshall <>
Date: 18 Jun 2006 12:36:42 -0700
Message-ID: <>

paul c wrote:
> Marshall wrote:
> > There's a lot of terminological discussion floating around right now,
> > and some of it is really bad.
> > [...]
> > A variable is a construct that has an associated value, and also
> > has some associated destructive update operation, usually
> > assignment. In statically typed languages, a variable has an
> > associated type, and updates to the variable must conform
> > to that type, possibly taking subtyping in to account.
> That is tidy, but one complaint - I believe that in r.t. variable means
> foremost a logical place-holder as in the fopl whereas I believe D&D
> coined the term relvar as a means to talk about imperative computer
> languages that implement an r.t. Not clear to me that these uses of
> variable and relvar are always comparable, e.g., what kind of
> destructive operation there can be for a fopl logical variable.

[First of all, I assume "r.t." means "relational theory" and "fopl" is "first order predicate logic." Correct me if I guessed wrong.]

Certainly there are different contexts in which the term "variable" is used, and across those different contexts there may be incompatible meanings. I was speaking of the programming languages theory ("PLT") context. So I am speaking of regular data variables, rather than logic variables--they are quite different.

Thanks for pointing out that distinction.

Marshall Received on Sun Jun 18 2006 - 21:36:42 CEST

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