On Tue, 20 Jan 2009, Stephen R. van den Berg wrote:
Henrik Grubbstr?m wrote:
On Tue, 20 Jan 2009, Stephen R. van den Berg wrote:
- if (x) return x;
- if ((x != 0) && stringp(x->type))
- return x->type;
- return RXML.nil;
This patch is unsafe, since it changes the handling of "" for results from
Oracle (Oracle doesn't differentiate between "" and NULL for string fields).
The first if (x) return x; always catches if (x != 0), or am I missing
something subtle here?
The subtlety here is that the StringNULL class has an lfun::`!() that
returns true, ie it won't be returned by the first if statement. The
second if statement tests if x is equal to zero by calling lfun::`==(),
which isn't implemented by StringNULL , and thus will fall back to the
low-level implementation of predef::`==(), which will see that the two
svalues have different types and thus aren't equal.
I.e. it only gets to the Oracle "if" when x == 0.
If my simplification is unsafe for Oracle, then maybe the existing logic
needs to be fixed?
The existing code works as intended, but might be a bit obscure (thus the
comments).
--
Sincerely,
Stephen R. van den Berg.
--
Henrik Grubbström [email protected]
Roxen Internet Software AB
