Re: Static typing (Was Re: Better support for garbage collection)

["Ken Garlington" <Ken.Garlington@computer.org>]

"David Starner" <dvdeug@x8b4e53cd.dhcp.okstate.edu> wrote in message
news:99ujqs$aai1@news.cis.okstate.edu...
: On Thu, 29 Mar 2001 05:02:56 GMT, Ken Garlington
<Ken.Garlington@computer.org> wrote:
: >: Then in Ada, a call "Mumble(1);" will resolve to the first Mumble.  But
: >: that's error prone.  A reasonable person might accidentally think it
: >: refers to the other one (because, after all, the number one is a
: >: perfectly reasonable floating-point number).
: >
: >As noted earlier, not according to the dictionary definition of
: >"floating-point".
:
: I think it's a little flaky to depend on dictionary definitions. : The
: only dictionary I have that defines this (the Free On-line Dictionary
: of Computing) defines it as "A number representation consisting of a
: mantissa, M, an exponent, E, and an (assumed) radix (or base)" which
: helps no one in this argument.

I usually use the Merriam-Webster online dictionary, which also defines
"floating-point." My hardcopy version of their Collegiate dictionary also
has a definition of "floating-point." I suspect many other dictionaries also
define the term.

IMHO it helps me *considerably* that there is a common meaning to the term,
and that that they all talk about a "representation" without necessarily
implying an *underlying hardware* representation. In fact, M-W is explicit
in this: "...in which a number is represented (as in a computer display)".
Therefore, there is support in general usage of form to determine if a
number is a floating-point number. If it's "flaky" to use traditions when
determining a "best" solution, then I guess I'm guilty as charged --
although, of course, the law would then be "flaky" as well, so I guess I
can't be convicted! ;)

As I noted in another post, if someone complained about Ada not requiring an
exponent as well as (or instead of) a decimal point, so that the literal
form would follow the "common" convention, I could understand that argument
(although it would be annoying to have to do this.)

: >:  I claim that this call
: >: should be ambiguous, and therefore illegal.  Likewise, "Mumble(1.0)"
: >: could be mistaken to refer to the wrong one (because, after all, 1.0 is
: >: an integer number).
: >
: >Not according to the dictionary definition of "integer".
:
: 1.0 is either zero or an integer (in this case 0) plus or minus one.

M-W says that it is one of the natural numbers, the negatives of these
numbers, or zero. A natural number is "the number 1 [not 1.0!]  or any
number (as 3, 12, 432) obtained by adding 1 to it one or more times: a
positive integer." (Zero is defined as "the arithmetic symbol 0".)

: So by the Free On-line Dictionary of Computing, it is an integer.

Actually, here's what FOLDOC says:

"integer: <mathematics> (Or 'whole number') One of the finite numbers in the
infinite set  ..., -3, -2, -1, 0, 1, 2, 3, ... An inductive definition of an
integer is a number which is either zero or an integer plus or minus one. An
integer is a number with no fractional part. If written in as a fixed-point
number, the part after the decimal (or other base) point will be zero.  A
natural number is a non-negative integer. "

Note that part about "if written in as [sic] a fixed-point number." What
this says to me is that an integer *is compatible with* a fixed-point
number, under certain circumstances. However, it clearly implies that we are
talking about two different "forms" of a number.

Just because in "the real world" we take short cuts doesn't change the fact
that these words have certain meanings. Generally, society encourages
non-rigorous usage of words, and since humans are interpreting them, it
works out OK (except, of course, that we often misunderstand each other as a
result). However, I believe that a language like Ada should pick a different
level of rigor in interpreting "words" (symbols), and that in particular I
wouldn't want it to be less rigorous than it is today.

: WordNet, and Webster's (1913) aren't as mathematically rigerous (an
: integer is a number that isn't a fraction or a mixed number?). Again,
: I don't see how the dictionary says that 1.0 is not an integer, and
: even if your's does, I don't see why that's definitive.

Well, I suppose you could argue that there are no definitive meanings to any
word, but I think there's a more generally-accepted notion in debate that
published works can be used to support an argument. Of course, you could
argue that it's "flaky" to use this concept in an argument. In fact, I think
the University of Texas did argue something similar, a few years ago.
(Actually, their argument was more expansive than that, IIRC...)