[Freeswitch-users] LUA pattern match question

[Steven Ayre]

"^%s*(.-)%s*$", "%1"

Lua uses it's own regex syntax, which is different from others you might be
used to (eg PCRE). Though there's a few similarities.

Match start of line, 0+ space, 0+ any character (as few times as possible,
so it doesn't include any trailing spaces), 0+ space, end of string
When matched replace the string with the matched portion.

It'll match any string.

It replaces it with the middle portion that excludes the leading/trailing
spaces.

In this case I assume ^$ are matching the start/end of lines not strings,
and matching just the final line so you're only left with the '0 Total'


On 18 July 2014 17:10, Sean Devoy <sdevoy at bizfocused.com> wrote:

>  Hi All,
>
>
>
> I have modified this excellent example LUA script (
> https://confluence.freeswitch.org/display/FREESWITCH/Lua+Intercom+example)
> to return “true” if an extension is in use and “false” otherwise”.  Just
> FYI: this is great for Cisco phones because an auto-answer (intercom)
> connection will interrupt the current call unless you block ALL intercom
> use.  With this I can sent intercom if not in use, or send as a standard
> call otherwise.  My complements to the original chef!
>
>
>
> My request is for someone to explain the pattern matching pattern used in
> this function:
>
>     function trim (s)
>
>        return (string.gsub(s, "^%s*(.-)%s*$", "%1"))
>
>     end
>
>
>
> It takes a string like this:
>
>
> “uuid,direction,created,created_epoch,name,state,cid_name,cid_num,ip_addr,dest,application,application_data,dialplan,context,read_codec,read_rate,read_bit_rate,write_codec,write_rate,write_bit_rate,secure,hostname,presence_id,presence_data,callstate,callee_name,callee_num,callee_direction,call_uuid,sent_callee_name,sent_callee_num
>
> d7bd917c-efca-4333-81f6-692c727069a2,inbound,2014-07-18
> 11:59:41,1405699181,sofia/external_noauth/4107673000 at 66.241.96.237,CS_EXECUTE,+14107673000,4107673000,66.241.96.237,BOOKKEEPING,voicemail,default
> voicemail_ESTA 40,XML,from-internal-ESTA,L16,8000,128000,PCMU,8000,64000,,
> fs_bfis.bizfocused.com,4107673000 at 66.241.96.237,,ACTIVE,,,,,,
>
>
>
> 1 total.”
>
>
>
> or just this:
>
> “
>
> 0 total.”
>
>
>
> And returns just the number and the “Total.” at the end, like “1 total.”
> Or “0 total.”
>
>
>
> I am fairly regex pattern savvy so I understand pattern matching, but I
> cannot decipher this LUA pattern.  I see it works, but I would like to
> understand how/why.
>
>
>
> Thanks as always,
>
> Sean
>
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>
> 
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