Drew’s suggestion can be implemented a different function in subr-x I guess.

—
Cheers, 
Bozhidar

On July 15, 2014 at 3:04:48 AM, Stephen J. Turnbull (stephen@xemacs.org) wrote:

Drew Adams writes:  

> The second arg, HOW, can be a regexp, giving the same behavior as now.  
> Alternatively, HOW can be (1) a character predicate or (2) a doubleton  
> plist (PROPERTY VALUE), where PROPERTY is a text property and VALUE is  
> one of its possible values.  

Why not just allow it to be any function returning an interval (with  
implicit argument = (point)), and provide appropriate functions to  
accomplish the tasks you propose?  

> By providing non-nil TEST you can test, for example:  
>  
> * Whether the actual value of text property `invisible' belongs to the  
> current `buffer-invisibility-spec'.  
>  
> * Whether a particular face is among the faces that are the value of  
> property `face'.  

A general predicate for HOW could do this, too.  

> Non-nil optional arg FLIP simply swaps the separators and the kept  
> substrings - regardless of HOW the separating is defined.  

This can be done for the "standard" functions by providing an optional  
FLIP argument, and using (lambda () (how-func 'flip-me)) as the HOW.  
Alternatively you could provide flipped standard HOW functions.  

I have no objection to a new function `split-string-à-la-drew' with  
any signature you like, but `split-string' should keep as simple a  
signature as possible.