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Diff of /sml/trunk/src/cml/src/IO/new-bin-io-fn.sml
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| revision 1322, Mon Apr 21 14:01:59 2003 UTC | revision 1323, Sat May 10 03:37:36 2003 UTC | |
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| # | Line 411 | Line 411 |
| 411 | end | end |
| 412 | *) | *) |
| 413 | ||
| 414 | (* IO event constructors: | |
| 415 | * We exploit the "functional" nature of stream IO to implement the event | |
| 416 | * constructors. These constructors spawn a thread to do the operation | |
| 417 | * and and write the result in an iVar that serves as the synchronization | |
| 418 | * value. | |
| 419 | * NOTE: this implementation has the weakness that it prevents shutdown when | |
| 420 | * everything else is deadlocked, since the thread that is spawned to actually | |
| 421 | * do the IO could proceed. | |
| 422 | *) | |
| 423 | local | |
| 424 | datatype 'a result = RES of 'a | EXN of exn | |
| 425 | fun doInput inputOp = let | |
| 426 | fun input arg = RES(inputOp arg) handle ex => EXN ex | |
| 427 | in | |
| 428 | fn arg => CML.guard (fn () => let | |
| 429 | val resV = SV.iVar() | |
| 430 | in | |
| 431 | CML.spawn (fn () => SV.iPut(resV, input arg)); | |
| 432 | CML.wrap(SV.iGetEvt resV, | |
| 433 | fn (RES x) => x | (EXN ex) => raise ex) | |
| 434 | end) | |
| 435 | end | |
| 436 | in | |
| 437 | val input1Evt = doInput input1 | |
| 438 | val inputEvt = doInput input | |
| 439 | val inputNEvt = doInput inputN | |
| 440 | val inputAllEvt = doInput inputAll | |
| 441 | end (* local *) | |
| 442 | ||
| 443 | ||
| 444 | (*** Output streams ***) | (*** Output streams ***) |
| 445 |
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