author | blanchet |
Sun, 01 May 2011 18:37:24 +0200 | |
changeset 42525 | 7a506b0b644f |
parent 42223 | 098c86e53153 |
child 43537 | 80803078552e |
permissions | -rw-r--r-- |
34136 | 1 |
(* Title: Pure/General/exn.ML |
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Author: Makarius |
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||
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Extra support for exceptions. |
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*) |
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||
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signature EXN = |
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sig |
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datatype 'a result = Result of 'a | Exn of exn |
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val get_result: 'a result -> 'a option |
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val get_exn: 'a result -> exn option |
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val capture: ('a -> 'b) -> 'a -> 'b result |
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val release: 'a result -> 'a |
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42223
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
14 |
val flat_result: 'a result result -> 'a result |
40234
39af96cc57cb
added Exn.interruptible_capture, which reraises interrupts as required by user-code (when Exn.capture is not immediately followed by Exn.release);
wenzelm
parents:
39472
diff
changeset
|
15 |
val map_result: ('a -> 'b) -> 'a result -> 'b result |
42223
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
16 |
val maps_result: ('a -> 'b result) -> 'a result -> 'b result |
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exception Interrupt |
39232
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
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val interrupt: unit -> 'a |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
19 |
val is_interrupt: exn -> bool |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
20 |
val interrupt_exn: 'a result |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
21 |
val is_interrupt_exn: 'a result -> bool |
40234
39af96cc57cb
added Exn.interruptible_capture, which reraises interrupts as required by user-code (when Exn.capture is not immediately followed by Exn.release);
wenzelm
parents:
39472
diff
changeset
|
22 |
val interruptible_capture: ('a -> 'b) -> 'a -> 'b result |
28459
f6a4d913cfb1
simplified Exn.EXCEPTIONS, flatten nested occurrences;
wenzelm
parents:
28444
diff
changeset
|
23 |
exception EXCEPTIONS of exn list |
32100
8ac6b1102f16
added flatten/flatten_list -- supercedes internal plain_exns;
wenzelm
parents:
31427
diff
changeset
|
24 |
val flatten: exn -> exn list |
8ac6b1102f16
added flatten/flatten_list -- supercedes internal plain_exns;
wenzelm
parents:
31427
diff
changeset
|
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val flatten_list: exn list -> exn list |
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val release_all: 'a result list -> 'a list |
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val release_first: 'a result list -> 'a list |
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end; |
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||
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structure Exn: EXN = |
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struct |
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||
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(* runtime exceptions as values *) |
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||
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datatype 'a result = |
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Result of 'a | |
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Exn of exn; |
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fun get_result (Result x) = SOME x |
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| get_result _ = NONE; |
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fun get_exn (Exn exn) = SOME exn |
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| get_exn _ = NONE; |
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fun capture f x = Result (f x) handle e => Exn e; |
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fun release (Result y) = y |
|
31427
5a07cc86675d
reraise exceptions to preserve original position (ML system specific);
wenzelm
parents:
29564
diff
changeset
|
48 |
| release (Exn e) = reraise e; |
23962 | 49 |
|
42223
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
50 |
fun flat_result (Result x) = x |
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
51 |
| flat_result (Exn e) = Exn e; |
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
52 |
|
39472 | 53 |
fun map_result f (Result x) = Result (f x) |
42223
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
54 |
| map_result f (Exn e) = Exn e; |
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
55 |
|
098c86e53153
more precise propagation of reports/results through some inner syntax layers;
wenzelm
parents:
40483
diff
changeset
|
56 |
fun maps_result f = flat_result o map_result f; |
39472 | 57 |
|
28444 | 58 |
|
39232
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
59 |
(* interrupts *) |
28444 | 60 |
|
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exception Interrupt = Interrupt; |
|
39232
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
62 |
|
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
63 |
fun interrupt () = raise Interrupt; |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
64 |
|
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
65 |
fun is_interrupt Interrupt = true |
40234
39af96cc57cb
added Exn.interruptible_capture, which reraises interrupts as required by user-code (when Exn.capture is not immediately followed by Exn.release);
wenzelm
parents:
39472
diff
changeset
|
66 |
| is_interrupt (IO.Io {cause, ...}) = is_interrupt cause |
39232
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
67 |
| is_interrupt _ = false; |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
68 |
|
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
69 |
val interrupt_exn = Exn Interrupt; |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
70 |
|
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
71 |
fun is_interrupt_exn (Exn exn) = is_interrupt exn |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
72 |
| is_interrupt_exn _ = false; |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
73 |
|
40234
39af96cc57cb
added Exn.interruptible_capture, which reraises interrupts as required by user-code (when Exn.capture is not immediately followed by Exn.release);
wenzelm
parents:
39472
diff
changeset
|
74 |
fun interruptible_capture f x = |
39af96cc57cb
added Exn.interruptible_capture, which reraises interrupts as required by user-code (when Exn.capture is not immediately followed by Exn.release);
wenzelm
parents:
39472
diff
changeset
|
75 |
Result (f x) handle e => if is_interrupt e then reraise e else Exn e; |
39af96cc57cb
added Exn.interruptible_capture, which reraises interrupts as required by user-code (when Exn.capture is not immediately followed by Exn.release);
wenzelm
parents:
39472
diff
changeset
|
76 |
|
39232
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
77 |
|
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
78 |
(* nested exceptions *) |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
79 |
|
28459
f6a4d913cfb1
simplified Exn.EXCEPTIONS, flatten nested occurrences;
wenzelm
parents:
28444
diff
changeset
|
80 |
exception EXCEPTIONS of exn list; |
28444 | 81 |
|
39232
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
82 |
fun flatten (EXCEPTIONS exns) = flatten_list exns |
69c6d3e87660
more abstract treatment of interrupts in structure Exn -- hardly ever need to mention Interrupt literally;
wenzelm
parents:
34136
diff
changeset
|
83 |
| flatten exn = if is_interrupt exn then [] else [exn] |
32100
8ac6b1102f16
added flatten/flatten_list -- supercedes internal plain_exns;
wenzelm
parents:
31427
diff
changeset
|
84 |
and flatten_list exns = List.concat (map flatten exns); |
23962 | 85 |
|
28444 | 86 |
fun release_all results = |
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if List.all (fn Result _ => true | _ => false) results |
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then map (fn Result x => x) results |
|
32100
8ac6b1102f16
added flatten/flatten_list -- supercedes internal plain_exns;
wenzelm
parents:
31427
diff
changeset
|
89 |
else raise EXCEPTIONS (flatten_list (List.mapPartial get_exn results)); |
28444 | 90 |
|
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fun release_first results = release_all results |
|
31427
5a07cc86675d
reraise exceptions to preserve original position (ML system specific);
wenzelm
parents:
29564
diff
changeset
|
92 |
handle EXCEPTIONS (exn :: _) => reraise exn; |
28444 | 93 |
|
23962 | 94 |
end; |
40483
3848283c14bb
treat pervasive "Interrupt" constructor as illegal -- superseded by Exn.Interrupt for internal use and Exn.is_interrupt/Exn.interrupt in user-space;
wenzelm
parents:
40234
diff
changeset
|
95 |
|
3848283c14bb
treat pervasive "Interrupt" constructor as illegal -- superseded by Exn.Interrupt for internal use and Exn.is_interrupt/Exn.interrupt in user-space;
wenzelm
parents:
40234
diff
changeset
|
96 |
datatype illegal = Interrupt; |
3848283c14bb
treat pervasive "Interrupt" constructor as illegal -- superseded by Exn.Interrupt for internal use and Exn.is_interrupt/Exn.interrupt in user-space;
wenzelm
parents:
40234
diff
changeset
|
97 |