Provide some documentation about the differences between XQuery regular expressions and those supported by Spencer's regex engine. Since SQL now exposes XQuery regexps with the LIKE_REGEX operator, I made this a standalone section designed to help somebody who has to translate a LIKE_REGEX query to Postgres. (Eventually we might extend Spencer's engine to allow precise implementation of XQuery, but not today.)
This also syncs the docs with the decision implemented in commit d5b90cd64 to desupport XQuery's 'x' flag for now.
Jonathan Katz and Tom Lane
0a97edb12e Doc: improve documentation around jsonpath regular expressions.
doc/src/sgml/func.sgml | 213 ++++++++++++++++++++++++++++++++++++++++++++++++-
doc/src/sgml/json.sgml | 33 ++++++--
2 files changed, 235 insertions(+), 11 deletions(-)