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Is there a way to temporarily suppress certain messages, so that I could write for example (with made-up syntax for that feature):

WithOff[Pattern::patv, rule = (f[x_Integer|{x__Integer}] :> g[x])];
rule2 = x_[x__] :> x;

and get no Pattern::patv message for rule, but do get one for rule2 iff the message was enabled at the beginning (that is, WithOff doesn't affect the on/off status of the message outside of its argument)?

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    $\begingroup$ Why can't you use Quiet[]? Quiet[rule = (f[x_Integer | {x__Integer}] :> g[x]), Pattern::patv] $\endgroup$ – J. M. will be back soon May 22 '12 at 11:18
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    $\begingroup$ @J.M.: Because I didn't know that and obviously my search-fu was lacking. $\endgroup$ – celtschk May 22 '12 at 12:06
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I agree completely with J.M., Quiet is the answer.

Implementing WithOff using Quiet is (as I'm sure you know) trivial. Here it is, just for fun:

ClearAll[WithOff]
SetAttributes[WithOff, HoldAll];
WithOff[msg_, expr_] := Quiet[expr, {msg}];
WithOff[Pattern::patv, rule = (f[x_Integer | {x__Integer}] :> g[x])];
rule2 = x_[x__] :> x;
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You can define the function:

 messageIsOn[msg_]:=Head[msg]===String

Which yields True if the message is on. Then do e.g:

msgStatus=messageIsOn[Pattern::patv]
If[msgStatus, Off[Pattern::patv]]
< some calculation suppressing message Pattern::patv >
(* Restore the message status *)
If[msgStatus, On[Pattern::patv]]
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    $\begingroup$ That's a very interesting solution. While Quiet is obviously the thing I've been looking for, this answer is actually the more interesting. I've never considered that Off might modify the message itself. Interestingly, assignment can be used to switch the message off, but not to switch it on. $\endgroup$ – celtschk May 22 '12 at 12:15
  • $\begingroup$ @celtschk I use this mainly in packages, where I don't want to suppress all messages, but only those I know to be harmless in this case. $\endgroup$ – Peter Breitfeld May 22 '12 at 15:19

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