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From: dxf <dxforth@gmail.com>
Newsgroups: comp.lang.forth
Subject: Re: Reverse SCAN SPLIT
Date: Fri, 18 Oct 2024 12:10:51 +1100
Organization: i2pn2 (i2pn.org)
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On 17/10/2024 9:29 pm, mhx wrote:
> On Thu, 17 Oct 2024 8:28:26 +0000, albert@spenarnc.xs4all.nl wrote:
> 
>> In article <nnd$231969a2$24a04042@87f25e33f755b9dd>,
> [..]
>> Compare to what I'm doing. Promoting the actual API specification
>> so that you can decide whether you want to actually use it.
>>
>>    $/
>>
>>
>>   STACKEFFECT: sc c --- sc1 sc2
>>
>>   DESCRIPTION: []
>>
>>   Find the first c in the string constant sc and split it at that
>>   address. Return the strings after and before c into sc1 and sc2
>>   respectively. If the character is not present sc1 is a null string
>>   (its address is zero) and sc2 is the original string. Both sc1 and
>>   sc2 may be empty strings (i.e. their count is zero), if c is the
>>   last or first character in sc .
> 
> Wil Baden chose to keep c in sc2. Do you have a reason to
> remove it?
> 
> It seems logical to remove it. I normally use lots of
> `1 /STRING' and `-LEADING' or `-TRAILING' sequences in further
> processing of Split-At-Char results, but not always.
> Maybe because an empty sc2 is less informative than an sc2 of
> size 1?

For Baden's implementation (below) it's easier for the application to
discard 'char' than have SPLIT do it.

: SPLIT        ( str /str char -- str+i /str-i str i )
    >R  2dup  R> SCAN  2SWAP  2 PICK - ;

SCAN is/was a machine-code routine and not readily changeable.