On 06/11/2011 02:18 AM, Charles Oliver Nutter wrote:
John Rose to the rescue... by reversing the order of foldArguments,
you can post-process the arguments *and* return value of the target.
See the other thread for an example.
SOLVED. Put it in the cookbook, Rémi! (or allow me to put it in the cookbook)
- Charlie
Send me a google id, I will allow you to have write access to the
repository.
In fact, this pattern is already hidden in the cookbook, take a look to
the memoize pattern
http://code.google.com/p/jsr292-cookbook/source/browse/trunk/memoize/src/jsr292/cookbook/memoize/RT.java
near line 31.
Rémi
On Fri, Jun 10, 2011 at 6:25 PM, Charles Oliver Nutter
<head...@headius.com> wrote:
On Fri, Jun 10, 2011 at 6:14 PM, Robert Fischer<smokejumpe...@gmail.com> wrote:
How is the assignment itself implemented in terms of MethodHandles?
What do you have to work with?
What I'm thinking is that you could implement the side-effect as part
of a MethodHandles#filterArguments call (one that doesn't actually
change the argument)? Just wrap that around a MethodHandles#identity
call. Won't that do it for you?
filterArguments replaces the argument at the given offset with the
result of the filter handle. It doesn't allow you to alter the return
value of the target. filterReturn allows you to change the return
value, but does not have access to arguments.
If you have the assignment implementation, but it returns
null/void/whatever, then use MethodHandles#foldArguments to insert a
second copy in front, and have the assignment be the map to the right.
I think that'll work.
foldArguments reinserts the results of passing all arguments to the
folding handle back into the parameter list, but does not do anything
to return value.
So far I've not been able to come up with a way to alter the return
value using the argument values. It only seems possible to do that
with an intermediate Java call that wraps everything else, and I stil
believe that defeats inlining the rest of the chain.
- Charlie
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