Re: [Scheme-reports] [scheme-reports-wg2] Re: Requesting early review of a character sequence library

[Alex Shinn <alexshinn@x>]

On Fri, Dec 19, 2014 at 1:54 PM, John Cowan <cowan@x> wrote:

Alex Shinn scripsit:

> From the discussions I had seen I thought the general direction
> for a new string API would be based on string-cursors, which have
> been implemented and used for some time in multiple Schemes.

I do provide the whole Chibi string-cursor API, I just provide a
higher level built on it that emulates strings, but with the
shareability/immutability advantages.

The problem is you force a duplication of APIs.  With a string API

you only have one type, and libraries may or may not provide

optional start/end arguments (probably yes when inputs may be

large as in SRFI-115, probably no for things like dealing with file

names).  If you introduce string cursors you can use the same

APIs and either ignore the start/end arguments or convert if

the source and target are using different conventions.  However,

if you introduce a character-span type you either need two versions

of every API or you need to convert from spans to strings, which

is potentially expensive.

> For special optimization cases something like this library may be
> useful, but I'd like to see it implemented and used for a while before
> we decide whether it's good for general purpose code, and further
> whether to standardize it.

Agreed, but SRFIs are not standards.

I was +1'ing Per's sentiment that this not be part of a standard.

From the lists you're sending it to it would seem this is intended for R7RS large.

-- 

Alex

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