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· Oct 18, 2018

$match or "?"

#Object Data Model #Caché

Hello all...

Is there two matching patterns in Caché, is there a difference in use one or the other?
Example:

USER>set a = "(1234)"

Using $match.

USER>w $match(a,"\([0-9]{4}\)")

USER>1

Using literal match (sorry if not correctly term expression)

USER>W a?1"("4n1")"

USER>1

What is different from using one or the other?

The 'a?1"("4n1")"' does this pattern exist only Caché.
Exists performance improvement with use pattern Caché?

Discussion (2)2
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Sean Connelly · Oct 18, 2018

Hi Tiago,

The ? pattern match is native to COS and has been in the product since day 1. You will also find it in GT.m and a few other fringe M systems, but probably nowhere else.

The $match feature was introduced back in 2012. It uses an external Regex library called ICU.

Both are highly optimised for general use cases (millions of operations per second).

The ? pattern matching syntax is less expressive than Regex, but this also makes it easy to learn and remember.

Regex would be the better choice for more complex pattern matching requirements.

Sean.

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