Re: [Scheme-reports] some questions on byte vectors + ports

[Alex Shinn <alexshinn@x>]

Hi,

On Wed, Jun 27, 2012 at 5:06 AM, Wolfgang De Meuter <wdmeuter@x> wrote:
>
> My entire implementation-stack is based on:
>        (a) the ability to read and write a byte vector from/to a sequential file/port in Scheme.
>        (b) the ability to position the current of a port to a given byte number (and subsequently read/write a byte vector at that position).
>        (c) the ability to encode / decode integers, floats and strings in a byte vector.
>
> I had a look at the R7RS report.
>        - I cannot find (b)
>        - I understood that (c) has been removed to the big language.
>
> Is (b) a conscious decision? Same question for (c) : to me, byte vectors are pretty useless if you don't have a minimal amount of comfort for encoding/decoding data types.

Yes, both are conscious.  The posix module slated for
the large language will cover (b).

Moving (c) to the large language was an obvious decision.

> And, given the fact that you no longer support this comfort, is there sufficient support to break down/ build up Scheme data types (integers, float,…) into / from raw bytes ? I.e., can I convert an integer or a float to a byte vector?

Yes, the primitives read-u8 and write-u8 are all you need
for this.  See the withdrawn SRFI-56 for a portable implementation.

-- 
Alex

_______________________________________________
Scheme-reports mailing list
Scheme-reports@x
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports