negative lookahead Regular Expression

[Daniel Lee]

I’m trying to find a regular expression that will route everying starting with R01 except R01MDOC.

Topic

[Daniel Lee]

I’ve done some more digging here.

[Jamin Gray]

Could you post the regex line in your tcl code?  I can’t duplicate the problem in hcitcl

Code:

hcitcl>set x R01MDOC
hcitcl>regexp {R01(?!MDOC)} $x match
0

hcitcl>set x R01GENLAB
hcitcl>regexp {R01(?!MDOC)} $x match
1

Seems to be working….

[Daniel Lee]

I get the same result as you in hcitcl but when I try to use the lookahead in the route and then use the route test tool it tells me that there are no routes defined.

[Daniel Lee]

I’ve been testing some more with this and can’t get a negative lookahead to work at all in a wildcard route.  Is this a limitation of the engine?  It works with the version of TCL the egine is using but will not work in the route.  I can’t figure out a way to write this logic without doing a negative lookahead.  Surely someone else has tried to do what I’m doing.

[Daniel Lee]

I figured this out.  I had to use the following expression:

R01(?!MDOC).*

I’m not sure why, hcitcl works without the .* at the end but the engine route will not work without it.

[Author]

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