xsd regular expression support for character classes

[mgsmith1000]

An rpc with an input parameter that is a string with a pattern "\w[\w_-]*" did not match the value "a-b". After stepping through with gdb, I found that regcomp() fails to compile this expression. The function regexp_xsd2posix() probably needs to replace '\w' with something that is valid in POSIX ERE.

When attempting to replace this with a regex that works with regcomp(), the pattern "[0-9A-Za-z-]" also didn't compile. Moving the '-' to the last character in the bracket expression ('[0-9A-Za-z-]') worked.

[dcornejo]

RFC 7950 sec 9.4.5 references W3 XML Schema Part 2 as the standard for the regular expressions used in the pattern statement: https://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#regexs

[olofhagsand]

Thanks for the reference link.
I added translation for \w, \d, \s, and some others. Please come back if there are other POSIX vs XSD regex mismatches.
However, it would be better if one could reuse an xsd regex check tool. Know of anyone?

[dcornejo]

these guys have a lot of tools I've found useful: https://yangcatalog.org/
(especially the YANG regex validator). If you explore their github, you can find the source for a version of grep (w3cgrep) that is behind their validator. It uses the regex lib from libxml2.