Re: read-all ?

[Andy Wingo <wingo@pobox.com>]

On Tue 22 Jan 2013 11:01, ludo@gnu.org (Ludovic Courtès) writes:

>>> Are the names right?
>
> ‘read-all’ doesn’t convey the idea that it’s textual (unlike the R6RS
> names).
>
> Perhaps ‘port-contents-as-string’, or ‘read-all-string’, or...?

What about read-string with an optional #:count argument ?

>> +  (let lp ((n start))
>> +    (if (< n end)
>> +        (let ((c (read-char port)))
>> +          (if (eof-object? c)
>> +              (- n start)
>> +              (begin
>> +                (string-set! buf n c)
>> +                (lp (1+ n)))))
>> +        (- n start))))
>
> As you note, this is fairly inefficient, like ‘get-string-n!’.

It is exactly what %read-delimited does, though, and that's the most
efficient thing we have.  read-string/partial! does something more
clever, but I don't understand it fully.  I was thinking (ice-9 ports)
could be appropriate if we exposed port buffers to scheme, because that
way we could read characters in bulk.  Dunno.

> Given that ‘string-set!’ is (unduly) costly, I wonder if consing all the
> chars and then calling ‘list->string’ wouldn’t be more efficient in time
> (it’d be less efficient in space.)

Probably not, I would say that the interface is more important than the
implementation.

So, proposal: read-all{,!} to read-string{,!} and add optional count
argument to read-string, and leave it in ice-9 rdelim.  WDYT?

Andy
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