regexp match loop on ^+
Tue Apr 13 18:38:56 CEST 2004
Magnus Ahltorp long ago implemented ENUM (RFC2916) support in Yxa.
ENUM lets you enter for example a SIP URI equivalent with an E.164 number in
DNS and uses regexps to make it possible to for example have DNS wildcard
entrys for your phone numbers. Magnus then found a little implementation
problem in implementing it in Erlang, because RFC2916 has examples containing
^+. On the last IETF there were a bit of talk about this. As far as I have
heard, ^+ is not invalid but it is very implementation dependent how well it
works. In Erlang, that is not very well :(
>From RFC2916 :
3.2.3 Example 3
* IN NAPTR 100 10 "u" "ldap+E2U" "!^+46(.*)$!ldap://ldap.se/cn=01!"
1> regexp:match("+461234", "+46(.*)$").
2> regexp:match("+461234", "\\+46(.*)$").
3> regexp:match("+461234", "^+46(.*)$").
On the third one, Erlang (R9C-0) regexp implementation loops.
regexp.erl was too complex for me to fix this myself, so I though I'd
raise the issue on the list so that someone else might perhaps at
least prevent the loop.
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