Re: patch: enhanced get diagnostics statement 2

A couple items for this patch:

The docs state that the variable to receive each diagnostic value needs
to be "of the right data type" but fails to specify what it is. I think
it'd be good to turn that <itemizedlist> into a table with three
columns: name, type, description.

This seems poor style:

+ case PLPGSQL_GETDIAG_ERROR_CONTEXT:
+ case PLPGSQL_GETDIAG_ERROR_DETAIL:
+ case PLPGSQL_GETDIAG_ERROR_HINT:
+ case PLPGSQL_GETDIAG_RETURNED_SQLSTATE:
+ case PLPGSQL_GETDIAG_MESSAGE_TEXT:
+ if (!$2)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("EXCEPTION_CONTEXT or EXCEPTION_DETAIL or EXCEPTION_HINT or RETURNED_SQLSTATE or MESSAGE_TEXT are not allowed in current diagnostics statement"),
+ parser_errposition(@1)));
+

I think we could replace this with something like

+ if (!$2)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("diagnostic value %s is not allowed in GET CURRENT DIAGNOSTICS statement", stringify(ditem->kind)),

Other than that, and a few grammar fixes in code comments, this seems
good to me.

--
Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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