[Haskell-cafe] STM: "nested atomically" error

Brandon Allbery allbery.b at gmail.com
Thu Jan 12 22:56:15 CET 2012

On Thu, Jan 12, 2012 at 16:50, Andrew Coppin <andrewcoppin at btinternet.com>wrote:

> My guess is that your "debug printing" is causing something to be
> evaluated when it otherwise wouldn't be, causing a transaction to begin
> within a transaction.

My guess is something is being lazily evaluated as usual, but if that is
forced within a transaction, well, last I checked the GHC I/O system used
STM internally so unsafePerformIO debug prints could well cause nested

brandon s allbery                                      allbery.b at gmail.com
wandering unix systems administrator (available)     (412) 475-9364 vm/sms
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