bug#47712: 27.1; Provide `string-display-width` function, which takes properties into account, `substring-width`

[Daniel Mendler]

On 4/12/21 3:21 PM, Eli Zaretskii wrote:
> Can we please see both methods benchmarked?  I'd also like to
> understand better in which situation you need to do this with
> thousands of strings in one go.  In any case, I presume that running
> your code on thousands of strings also takes some time, let alone
> conses many strings.

Sure, I can prepare something in order to check if the slowdown is 
significant.

> string-width is from my POV a historical accident.  The accident
> happened long ago enough to preclude deleting it, but I'd like to
> limit its use as much as possible.  I certainly would like to avoid
> extending it or making it support more features (it currently supports
> only composed characters).

Okay, fair enough. I am all for removing/obsoleting functionality which 
is considered an accident as long as a good alternative exists. But if 
no acceptable alternative exists, the function has a justification and 
then it may also be possible to improve upon it.