Re: patch: function xmltable

Pavel Stehule wrote:
>
> I used your proposed way based on Restarget

Thanks. Some more tweaking to go yet before I consider this
committable, but it's much better now. Here's v28. I changed a few
things:

- make expression evaluation code more orthodox:
1. avoid PG_TRY, use a ExprContext shutdown callback instead
2. use a "Fast" evaluator, for calls past the first one
3. don't look up fmgrinfos until execution time
4. don't duplicate get_expr_result_type
- make parser accept DEFAULT namespace. Only xml implementation barfs.
(this means we lost the errposition pointer, but I don't really
care. We could fix it if we cared)
- clean up parse analysis code a little bit
- move decls/struct defs to better locations in source code
- remove leftover "namespaces" in TableExprState
- pgindent the whole mess.

I don't like the xml.c code and the "evalcols" flag. That's next on my
list to fix.

I don't think to_xmlstr() is necessary, considering xml_text2xmlChar.
We could just apply a cast of the source cstring to xmlChar.

--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services