Description

• According to the docs for the re module, the POSIX class ascii should match Character codes 0-127.

• Examples show it matches characters 0..255. This is different behaviour to other PCRE-based regex implementations.

To Reproduce

Eshell V10.7  (abort with ^G)
1> re:run(<<"ü"/utf8>>, "[[:ascii:]]", [unicode]).
{match,[{0,2}]}
2> re:run(<<"ü">>, "[[:ascii:]]").
{match,[{0,1}]}
3> re:run(<<"ü"/utf8>>, "[[:ascii:]]").
{match,[{0,1}]}
4> re:run("ü", "[[:ascii:]]").         
{match,[{0,1}]}

Expected behaviour

The ascii POSIX character class should match only code points in the range 0..127 as documented and as consistent with other PCRE-based implementations. In these implementations, [[:ascii:]] is equivalent to \p{block=basic_latin} which is the range 0..127.

Environment

Reproduced on:

Erlang/OTP 22 [erts-10.7] [source] [64-bit] [smp:2:2] [ds:2:2:10] [async-threads:1] [hipe]
Erlang/OTP 23 [erts-11.1.6] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [hipe]