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Re: #\a octothorpe syntax vs SRFI 10
On Thu, 30 Dec 2004, Aubrey Jaffer wrote:
>In the updated srfi-58.html I sent to the editor I have eliminated the
>#Axxx syntax. The rank digit(s) will be required.
My own preference would be something like [3 instead of #A3(
making the bracket-number combination (without a separating space)
a token that means "start an array of this numerical order."
Scheme makes parentheses separating characters, but brackets,
officially, are not parentheses. I think openbracket immediately
followed by a number is a much nicer (more succinct) way to
indicate array rank.
You could extend it for Uniform arrays, if you wanted: [3u8
would mean "start a rank 3 array of 8-bit unsigned integers."
it's two fewer characters every time an array is used, and
the symbols are visually simpler. I think that's important,
> | > | So, for example, the two-by-two array of unsigned 16-bit integers from
> | > | the document might be written as #,(ARRAY 2 u16 (0 1) (2 3)).
or as [2u16 [ 0 1][ 2 3]] . This treats openbrace as a non-delimiter
character (allowing rank, etc, prefixes to be appended) and close
brace as a delimiter.
> | > | General object arrays' types would be OBJECT (so #(FOO 1 #T ())
> | > | could also be written #,(ARRAY OBJECT FOO 1 #T ()))
Or as [ FOO 1 #T '() ]
> | > and character
> | > | arrays' types would be CHAR (so "foo" could alternatively be
> | > | written #,(ARRAY CHAR #\f #\o #\o)).
I don't think that "string" as a misspelling of "character array"
is consistent with the modern universe of character sets and encodings.
I think that
[c #\f #\o #\o ] should be a different entity than "foo."
>English doesn't much help remember Scheme exponent markers:
> The letters `s', `f', `d', and `l' specify the use of SHORT, SINGLE,
> DOUBLE, and LONG precision, respectively.
>I don't usually think of a DOUBLE as shorter than a LONG. And where
>did `f' for SINGLE come from? Maybe it is a C-ism. In any case, it
>is one of five characters (with 'e') rather than one of five longer
>sequences to remember.
Actually, scheme exponent markers other than default-precision 'e'
are 's' 'f' 'd' and 'l', for 'short', 'float', 'double', and 'long',
which only makes sense if you are a C programmer. The idea with C
was that these names would be distributed among the hardware float
types available, such that they are a nondecreasing sequence in
precision, although some precisions may be known by more than one
name. Unfortunately, rather than actually carry through with the
plan, most C compilers now treat 'double' and 'long' as identical
precisions, while introducing new tokens, 'long long' or 'extended'
to denote even bigger precisions.
Personally, I think this is a wart in scheme numeric syntax; these
are properly about exactness and belong with the exactness prefix,
not in the exponent marker.