Re: How to check whether a character (or one-character string) is a letter?

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Marcin Borkowski <mbork@wmi.amu.edu.pl> writes:

> Hello,
>
> this is a problem I have.
>
> Assume that I have a character (taken from some string, which in turn is
> copied from the buffer - so it need not be ASCII).  What is the best way
> to check whether it is a letter within ASCII range?
>
> The reason I'm asking is that I'm writing a function which converts an
> arbitrary string to a valid (and nice) filename (e.g., only letters and
> hyphens) - so basically I want to walk a string character by character
> and convert any space to a hyphen and omit any other non-letter.  Am I
> reinventing the wheel?

The safest thing is probably still replace-regexp-in-string. You can use
the [:ascii:] character class to strip out anything that isn't ascii,
with a regexp like "[^[:ascii:]]+". Messing with the string at the
character level shouldn't be necessary.

Eric