deduplicating lambda methods

[B. Blaser]

On 27 March 2018 at 20:22, B. Blaser <bsrbnd at gmail.com> wrote:
> On 27 March 2018 at 19:33, Vicente Romero <vicente.romero at oracle.com> wrote:
>>
>>
>> On 03/27/2018 12:58 PM, Brian Goetz wrote:
>>>
>>> It looks like there were no changes in the outcome, perhaps because there
>>> were no within-file duplications in the JDK.  (Which I believe.)  A more
>>> streams/Rx/CompletableFuture-heavy codebase would likely see an improvement.
>>
>>
>> right, no difference :(, let's see what happens with Liam's numbers :)
>
> Did you include the improvement I suggested to compare local variables
> *by name* instead of * by symbol* ?
> If not, there's quite no chance to find duplicates excepted trivial ones ;-)

Field access symbols don't seem to be '==' neither (is that right?).
So, to begin with something simple, I would compare all identifiers by name:

TreeDiffer.visitIdent:
    result = tree.sym.name == that.sym.name;

TreeDiffer.visitSelect:
    result = scan(tree.selected, that.selected) && tree.sym.name ==
that.sym.name;

TreeHasher.visitIdent:
    hash(sym.name);

TreeHasher.visitSelect:
    hash(tree.sym.name);

I'll try to write it a bit better, run some more tests and find a
couple of examples like:

    Runnable r1 = () -> {
        Runnable r2 = () -> {};
    };
    r1 = () -> {
        Runnable r2 = () -> {};
    };

    r1 = () -> {
        Class<?> c = Integer.class;
    };
    r1 = () -> {
        Class<?> c = Integer.class;
    };

What do you think?

Thanks,
Bernard


> Bernard
>
>> Vicente