FHIR Chat · XML Schema for regex?

This comment (GF#19891) suggests that FHIRPath standardize on the regex schema (SHALL, instead of SHOULD). We intentionally made it a recommendation to reduce implementer burden, any thoughts on whether we should go ahead and rqeuire XML Schema regex?

Grahame Grieve (Feb 01 2019 at 04:07):

is there a way to find out what libraries are compliant? a test set?

Lloyd McKenzie (Feb 01 2019 at 04:15):

The operation is pretty useless if it's not implemented consistently across platforms...

Bryn Rhodes (Feb 01 2019 at 04:16):

https://stackoverflow.com/questions/15819919/where-can-i-find-unit-tests-for-regular-expressions-in-multiple-languages

Bryn Rhodes (Feb 01 2019 at 04:17):

And there's RegexBuddy, we can have it just translate flavors for us: https://www.regular-expressions.info/refflavors.html

Bryn Rhodes (Feb 01 2019 at 04:18):

245 flavors!

Grahame Grieve (Feb 01 2019 at 04:19):

the stack overflow reference is nice, but which is the schema one(s)?

Bryn Rhodes (Feb 01 2019 at 04:20):

https://www.regular-expressions.info/xml.html

Bryn Rhodes (Feb 01 2019 at 04:21):

Reading up on the XML Schema one there is interesting.

Bryn Rhodes (Feb 01 2019 at 04:22):

Based on that writeup, my guess is that all of those test suites would fail on an XML Schema regex engine.

Bryn Rhodes (Feb 01 2019 at 04:22):

(Because they would test features the XML Schema regex doesn't support)

Grahame Grieve (Feb 01 2019 at 04:26):

XML regular expressions don't have any tokens like \xFF or \uFFFF to match particular (non-printable) characters. You have to add them as literal characters to your regex. If you are entering the regex into an XML file using a plain text editor, then you can use the XML syntax. Otherwise, you'll need to paste in the characters from a character map.