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Regular Expressions in num-exp

lefbaca01
Level 1
Level 1

Hello All,

I had a problem on my SRST gateway with num-exp insterting a repeating pattern into my 7-digit dialing when in fallback mode.

For a brief example, the 7digit internal dialing is 21621.. or 21622..

The num-exp statement of 'num-exp 2... 2162...' was not allowing me to 7-digit dial directly from one IP phone to another while in fallback mode.

When I dialed 2162154 the 2162 would hit the num-exp and be expended to 2162162.

I have a work around that uses a voice translation-rule, applied to the call-manager-fallback config that will translate a 7-digit dialed string to the 4 digit dialed string which then hits the 4-digit to 7-digit num-exp and it is working fine.

However, I was wondering if there is a way to  use regular expressions in num-exp so that perhaps I can skip the intermediate step of using the translation-rule. Based off my existing translation-rules that are working properly, I figured something like this might work for num-exp:

'num-exp /^2\([12]..$\)/ /2162\1/'

But when I try to issue a num-exp with a regular expression I get the following message.

Incorrect format for Number macro pattern

        regular expression must be of the form  ^((\+)?([0-9#*A-F.]|(\\\*))+(\$)?)$

I have tried a number of different combinations with no success.  I always get the same message.  The regular expression that I tried first was:

'num-exp ^2... 2162...'

This is when I first saw the "Incorrect format..." message and figured that is must be possible.  Is this just a generic warning similar to when you try to use complex regular expressions with the 'translation-rule' command vs. the 'voice translation-rule' command and in reality you cannot use regular expressions in the num-exp command?

Thank you,

Leo

1 Accepted Solution

Accepted Solutions

Chris Deren
Hall of Fame
Hall of Fame

Translation rules or dialplan-pattern is what you want to use, I am not aware of any regular expression support with num-exp, why do you insist on using num-exp?

Chris

View solution in original post

4 Replies 4

Chris Deren
Hall of Fame
Hall of Fame

Translation rules or dialplan-pattern is what you want to use, I am not aware of any regular expression support with num-exp, why do you insist on using num-exp?

Chris

Hi Chris,

Thank you for taking the time to answer my question.  It looks like the answer is no, num-exp does not support regular expressions.

I don't insist on using num-exp for this I was just hoping to kill two birds with one stone and possibly skip the intermediate step of translating the 7-digits dial to 4-digits using a translation-rule just to expand from 4-digit to 7 again.  This is only an issue while in SRST if a user tries to dial using 7-digits.  We have a 7-digit internal dialing scheme and normally my num-exp is just to expand the 4 digits sent from the telco to our 7-digit internal dialing.  The problem is that both our prefix and part of our DID range start with 21 so while in SRST if a user tried to dial a 7-digit DN, say 2162154, after they dialed the 4th digit (2162) that pattern would hit the num-exp and get expanded to 2162162.  I was hoping to create a num-exp using a regular expression that would only expand a four digit string that begins with a 2 to seven digits and not any string that begins with a 2.  This would 1) expand the four digits sent from the telco and 2) not match a seven digit string that begins with a 2 such as 2162154 which may be dialed by a user.

Again, this is only an issue while in SRST and I have a pretty good work around so I'm fine with not being able to use a regular expression as part of my num-exp config.  I just thought it would be a cool application of a regular expression if it was possible.

Thanks again for answering my question.

Leo

Leo,

Translation rules are the way to handle this type of scenario, so if that is what you used you've picked the right solution.

HTH,

Chris

wdelaughter
Level 1
Level 1

I usually don't necro thread, but I couldn't find this documented out anywhere else.  The above is incorrect about num-exp macros.  It does accept a limited subset of wildcards.  It will not accept ^ because by default it will only match the front of a number and not the middle unlike translations.  It will accept $ at the end which will prevent it from matching partial strings.  It will accept . for a single character wildcard.  It will accept * for multiple repeats of the previous character.  So to solve the original problem you just needed to add a $ at the end of your first number.

 

num-exp 2...$ 2162...

 

show dialplan number 2555 will show 2162555

show dialplan number 255567 will show 255567

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