Raffaele Ricciardi wrote:
- start emacs -Q
- evaluate this forms:
(string-match "[:xdigit:]" "0")
(string-match "[:xdigit:]" "a")
(string-match "[:alnum:]" "5")
They should return non-nil, but they return nil instead.
From the elisp manual:
34.3.1.2 Character Classes
Here is a table of the classes you can use in a character alternative,
^^^^^^^^^^^^^^^^^^^^^^^^^
34.3.1.1 Special Characters in Regular Expressions
[...]
`[ ... ]'
is a "character alternative", which begins with `[' and is
terminated by `]'
Therefore you must write eg
(string-match "[[:xdigit:]]" "0")