What is Expressiveness in a Computer Language

[David Hopwood]

Marshall wrote:
> Torben Ægidius Mogensen wrote:
> 
>>That's not true.  ML has variables in the mathematical sense of
>>variables -- symbols that can be associated with different values at
>>different times.  What it doesn't have is mutable variables (though it
>>can get the effect of those by having variables be immutable
>>references to mutable memory locations).
> 
> While we're on the topic of terminology, here's a pet peeve of
> mine: "immutable variable."
> 
> immutable = can't change
> vary-able = can change
> 
> Clearly a contradiction in terms.

But one that is at least two hundred years old [*], and so unlikely to be
fixed now.

In any case, the intent of this usage (in both mathematics and programming)
is that different *instances* of a variable can be associated with different
values.

[*] introduced by Leibniz, according to <http://members.aol.com/jeff570/v.html>,
    but that was presumably in Latin. The first use of "variable" as a noun
    recorded by the OED in written English is in 1816.

-- 
David Hopwood <david.nospam.hopwood at blueyonder.co.uk>