[Eager-future-devel] Interaction between pexec macro and loop macro?

[Mark Brown]

I'm having difficulty in understanding behaviour when futures are 
created in loops defined by the loop macro. Here's a very simple example:

First, load eager-future2 using quicklisp.

CL-USER> (ql:quickload :eager-future2)
To load "eager-future2":
   Load 1 ASDF system:
     eager-future2
; Loading "eager-future2"

(:EAGER-FUTURE2)

Now create a bunch of futures in a loop with pexec, using a loop 
variable in the future, then yield them. For the following code, I 
expect a list of values from 0 to 9 but I get something strange:

CL-USER> (loop for k in (loop repeat 10 for i = 0 then (+ 1 i) collect 
(eager-future2:pexec (list i))) collect (eager-future2:yield k))
((7) (7) (8) (9) (9) (9) (9) (9) (9) (9))

Instead of using pexec, let's use a separate function to create our thunk.

CL-USER> (defun make-thunk (i) (lambda () (list i)))
MAKE-THUNK

Now instead of using pexec we use pcall with our thunk-maker. And the 
result is as expected.

CL-USER> (loop for k in (loop repeat 10 for i = 0 then (+ 1 i) collect 
(eager-future2:pcall (make-thunk i))) collect (eager-future2:yield k))
((0) (1) (2) (3) (4) (5) (6) (7) (8) (9))


Note that using (pcall (lambda () (list i))) also does NOT work.

Am I misunderstanding something?