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| ID | Project | Category | View Status | Date Submitted | Last Update | ||||
|---|---|---|---|---|---|---|---|---|---|
| 0000223 | mercury | Bug | public | 2011-10-24 08:02 | 2011-11-03 12:08 | ||||
| Reporter | colanderman | ||||||||
| Assigned To | wangp | ||||||||
| Priority | normal | Severity | minor | Reproducibility | always | ||||
| Status | resolved | Resolution | fixed | ||||||
| Product Version | |||||||||
| Target Version | Fixed in Version | ||||||||
| Summary | 0000223: thread.mvar.init/0 and thread.semaphore.init/1 should be marked impure | ||||||||
| Description | thread.mvar.init/0 and thread.semaphore.init/1 are obviously impure but are not marked as such, leading to logical inconsistencies such as this: main(!IO) :- M1 = init, M2 = init, put(M1, 1, !IO), take(M2, _, !IO). not being equivalent to this: main(!IO) :- M1 = init, M2 = M1, put(M1, 1, !IO), take(M2, _, !IO). (The former will block but the latter will not.) They should be marked impure or removed from the library. | ||||||||
| Tags | No tags attached. | ||||||||
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wangp (developer) 2011-10-24 09:37 |
That's true. They were added so that mvar and semaphore mutables could be initialised without the I/O state arguments. Before marking them impure, I would like to see either or both: - mutables allowed to be initialised by impure functions - mutables initialised by a predicate call with access to the I/O state |
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juliensf (administrator) 2011-10-24 16:10 |
(1) mutables allowed to be initialised by impure functions This would be fine, for consistency we should allow calls to semipure functions too. (Once this is done mvar.init etc can just be made impure.) (2) mutables initialised by a predicate call with access to the I/O state This is a bit more tricky. The third argument of a mutable declaration is currently a value, not a call. In order to have a predicate call in the third argument this will need to change and probably in a way that will break quite a bit of code that already uses mutables. |
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wangp (developer) 2011-11-03 12:08 |
Fix committed. |
| Notes |
| Issue History |
|||
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2011-10-24 08:02 | colanderman | New Issue | |
| 2011-10-24 09:37 | wangp | Note Added: 0000368 | |
| 2011-10-24 16:10 | juliensf | Note Added: 0000371 | |
| 2011-10-24 16:10 | juliensf | Status | new => acknowledged |
| 2011-11-03 12:08 | wangp | Note Added: 0000380 | |
| 2011-11-03 12:08 | wangp | Status | acknowledged => resolved |
| 2011-11-03 12:08 | wangp | Resolution | open => fixed |
| 2011-11-03 12:08 | wangp | Assigned To | => wangp |
| Issue History |