transparent lambda

[Zdenek Tronicek]

I think Neal is looking for the SYNTAX. Perhaps he will write more.

Z.
-- 
Zdenek Tronicek
FIT CTU in Prague


Peter Levart napsal(a):
> I checked the "Jump" and "UnmatchedTransfer" classes in the BGGA
> 2008-08-11 prototype on javac.info. The abstract Jump class has an
> abstract thread() method that returns a thread. I haven't looked into what
> code is generated by the prototype javac in such cases, but I suspect
> javac generates Jump sub-classes for particular non-local transfers. Do
> you perhaps know if there is a document describing the implementation
> details of the prototype regarding non-local transfers?
>
> I may have unknowingly re-spawn the same idea once again, but does the
> BGGA prototype generate code with same semantics as described by Neal when
> he wrote the following:
>
> http://mail.openjdk.java.net/pipermail/closures-dev/2009-December/000506.html
>
> I thought he was looking for a solution of how the desired semantics could
> be implemented.
>
> Peter
>
> On Monday 04 January 2010 12:58:28 Zdenek Tronicek wrote:
>> Did you have a look at the closures prototype? I think you describe the
>> way how non-local transfer is implemented.
>>
>> Z.
>> --
>> Zdenek Tronicek
>> FIT CTU in Prague
>>
>
> P.S. Analogously to the previous non-local return, labeled yield is
> similar but also checks the target of the yield:
>
>
> @Shared #void() y1 = null;
>
> #int() one = #One() {
>   if (y1 == null)
>     y1 = #(){ yield One: 1; };
>
>   y1();
> };
>
> System.out.println(one()); // prints "1"
> System.out.println(one()); // throws exception
>
>
>
> // With following helper class:
>
> public class YieldInt extends RuntimeException {
>   public final Object initiatingLambda,
>   public final Object targetLambda; // null in case of return from method
>   public final int retval;
>   public YieldInt(Object initiatingLambda, Object targetLambda, int
> retval) {
>     this.initiatingLambda = initiatingLambda;
>     this.targetLambda = targetLambda,
>     this.retval = retval;
>   }
> }
>
>
> // The above could be translated into:
>
> @Shared #void() y1 = null;
>
> class One implements #int() {
>   public int invoke() {
>     #void() tmp$y1 = null;
>     try {
>       // #One() body begin
>       if (y1 == null) {
>         tmp$y1 = new #void()() {
>           public void invoke() {
>             throw new YieldInt(this, One.this, 1);
>           }
>         };
>         y1 = tmp$y1;
>       }
>
>       y1();
>       // #One() body end
>     }
>     catch (YieldInt yInt)
>     {
>       if (yInt.targetLambda == this && (yInt.initiatingLambda == tmp$y1))
>         return yInt.retval;
>       else
>         throw yInt;
>     }
>   }
> }
>
> #int() one = new One();
>
> System.out.println(one()); // prints "1"
> System.out.println(one()); // throws YieldInt
>