Force, rentrent promise promise/e (or, pam/e is too strict)

I have the following program:

#lang racket

(require data/enumerate
         data/enumerate/lib)

(pam/e (λ (x) x)
       (letrec ([expr/e (delay/e
                         (or/e
                          natural/e
                          (pam/e (λ (x) x)
                                 expr/e
                                 #:contract any/c)))])
         expr/e)
       #:contract any/c)

And when I run it, I get:

. . racket/racket/collects/racket/private/promise.rkt:104:10: force: reentrant promise `promise/e'

I suspect the problem is related to the inner pam/e, because when I turn the inner expression:

(pam/e (λ (x) x)
    expr/e
    #:contract any/c)))])

Into: expr/e the program runs normally.

For now I found data/enumerate/unsafe, and my program seems to work fine in it.

A smaller program breaks too:

#lang racket/base
(require pict/tree-layout
         data/enumerate
         data/enumerate/lib)

(define bt/e
  (delay/e
   (or/e (single/e #f)
         (pam/e (λ (x) (tree-layout (car x) (cdr x)))
                (cons/e bt/e bt/e)
                #:contract tree-layout?))))

(from-nat bt/e 0)

On Wed, Mar 2, 2016 at 2:00 PM, Leif Andersen notifications@github.com
wrote:

For now I found data/enumerate/unsafe, and my program seems to work fine
in it.

—
Reply to this email directly or view it on GitHub
#4 (comment).

Jay McCarthy
Associate Professor
PLT @ CS @ UMass Lowell
http://jeapostrophe.github.io

       "Wherefore, be not weary in well-doing,
  for ye are laying the foundation of a great work.

And out of small things proceedeth that which is great."
- D&C 64:33

I just got back to looking into this and I'm not seeing the error anymore, although I think I did see if when Leif first posted this.

Maybe one of the compiler optimization fixes fixed it?

I'm on commit 509da64135f412acd8522747daa3568524ac59ae and I have the error.

On Wed, Mar 9, 2016 at 6:06 PM, Robby Findler notifications@github.com
wrote:

I just got back to looking into this and I'm not seeing the error anymore,
although I think I did see if when Leif first posted this.

Maybe one of the compiler optimization fixes fixed it?

—
Reply to this email directly or view it on GitHub
#4 (comment).

Jay McCarthy
Associate Professor
PLT @ CS @ UMass Lowell
http://jeapostrophe.github.io

       "Wherefore, be not weary in well-doing,
  for ye are laying the foundation of a great work.

And out of small things proceedeth that which is great."
- D&C 64:33

I'm two days ahead of you, but I don't really see any obvious commits that
would fix it. Nevertheless, I get the expected error for both of these
programs, namely:

delay/e-expression: broke its own contract

promised: two-way-enum?

produced: #<infinite-one-way-enum...>

in: an and/c case of

  (and/c

   infinite-enum?

   two-way-enum?

   flat-enum?)

contract from: /Users/robby/tmp.rkt

blaming: /Users/robby/tmp.rkt

(assuming the contract is correct)

at: /Users/robby/tmp.rkt:7.0

context...:

/Users/robby/git/exp/plt/racket/collects/racket/contract/private/blame.rkt:156:0:
raise-blame-error16

/Users/robby/git/exp/plt/racket/collects/racket/private/promise.rkt:104:10

/Users/robby/git/exp/plt/racket/collects/racket/private/more-scheme.rkt:265:2:
call-with-exception-handler

/Users/robby/git/exp/plt/racket/collects/racket/private/promise.rkt:96:0:
force/generic

/Users/robby/git/exp/plt/extra-pkgs/data/data-enumerate-lib/data/enumerate/private/core.rkt:1076:9

/Users/robby/tmp.rkt: [running body]

I get

force: reentrant promise `promise/e'
  context...:
   /Users/jay/Dev/scm/plt/racket/collects/racket/private/promise.rkt:96:0:
force/generic
   ...private/base.rkt:107:23

 /Users/jay/Dev/scm/plt/racket/collects/racket/contract/private/base.rkt:159:5

 /Users/jay/Dev/scm/plt/racket/collects/racket/contract/private/list.rkt:339:2

 /Users/jay/Dev/scm/plt/racket/collects/racket/contract/private/arrow-higher-order.rkt:454:2

 /Users/jay/Dev/scm/plt/racket/collects/racket/contract/private/arr-i.rkt:1094:2:
un-dep/maybe-chaperone
   ...rivate/arr-i.rkt:914:19
   /Users/jay/Dev/scm/plt/racket/collects/racket/private/kw.rkt:1585:36
   ...private/more.rkt:576:56

 /Users/jay/Dev/scm/plt/extra-pkgs/data-enumerate-lib/data-enumerate-lib/data/enumerate/private/more.rkt:601:13:
temp203
   /Users/jay/Dev/scm/plt/racket/collects/racket/private/promise.rkt:96:0:
force/generic

 /Users/jay/Dev/scm/plt/extra-pkgs/data-enumerate-lib/data-enumerate-lib/data/enumerate/private/core.rkt:1074:9
   /tmp/t.rkt: [running body]

 /Users/jay/Dev/scm/plt/extra-pkgs/compiler-lib/compiler-lib/compiler/commands/test.rkt:176:16
t.rkt: raco test: test raised an exception

Compilation exited abnormally with code 1 at Wed Mar  9 19:04:46

If you expect these programs to both error, how do you think we should
write down recursive one-way enumerations?

Jay

On Wed, Mar 9, 2016 at 7:01 PM, Robby Findler notifications@github.com
wrote:

I'm two days ahead of you, but I don't really see any obvious commits that
would fix it. Nevertheless, I get the expected error for both of these
programs, namely:

delay/e-expression: broke its own contract

promised: two-way-enum?

produced: #<infinite-one-way-enum...>

in: an and/c case of

(and/c

infinite-enum?

two-way-enum?

flat-enum?)

contract from: /Users/robby/tmp.rkt

blaming: /Users/robby/tmp.rkt

(assuming the contract is correct)

at: /Users/robby/tmp.rkt:7.0

context...:

/Users/robby/git/exp/plt/racket/collects/racket/contract/private/blame.rkt:156:0:
raise-blame-error16

/Users/robby/git/exp/plt/racket/collects/racket/private/promise.rkt:104:10

/Users/robby/git/exp/plt/racket/collects/racket/private/more-scheme.rkt:265:2:
call-with-exception-handler

/Users/robby/git/exp/plt/racket/collects/racket/private/promise.rkt:96:0:
force/generic

/Users/robby/git/exp/plt/extra-pkgs/data/data-enumerate-lib/data/enumerate/private/core.rkt:1076:9

/Users/robby/tmp.rkt: [running body]

—
Reply to this email directly or view it on GitHub
#4 (comment).

Jay McCarthy
Associate Professor
PLT @ CS @ UMass Lowell
http://jeapostrophe.github.io

       "Wherefore, be not weary in well-doing,
  for ye are laying the foundation of a great work.

And out of small things proceedeth that which is great."
- D&C 64:33

I still don't see why the error went away for me, but the obvious thing to guess is that something happened in the two days of git commits. And yes, I did indeed see that error before.

Meanwhile, here's the program I think that you wanted?

#lang racket/base
(require pict/tree-layout
data/enumerate
data/enumerate/lib)

(define bt/e
(delay/e
 (or/e (single/e #f)
       (pam/e (λ (x) (tree-layout (car x) (cdr x)))
              (cons/e bt/e bt/e)
              #:contract tree-layout?))
 #:two-way-enum? #f))

(for/list ([i (in-range 1 10)])
  (binary-tidier (from-nat bt/e i)))

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Force, rentrent promise promise/e (or, pam/e is too strict) #4

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LeifAndersen commented on Mar 2, 2016

jeapostrophe commented on Mar 2, 2016

rfindler commented on Mar 9, 2016

jeapostrophe commented on Mar 9, 2016

rfindler commented on Mar 10, 2016

jeapostrophe commented on Mar 10, 2016

rfindler commented on Mar 10, 2016

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