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How does ruby prevent you from doing non-transactional things between 'do' and 'end'?

• slondr 3y ago
  The same way you would be prevented from doing non-transactional things between calls to transaction.start() and transaction.end()
  • mrkeen 3y ago
    When I write this: someTransaction = do incrementCounter writeFile "foo.txt" "bar" decrementCounter I get this: src/Lib.hs:11:5: error: • Couldn't match type ‘IO’ with ‘STM’ Expected: STM () Actual: IO () • In a stmt of a 'do' block: writeFile "foo.txt" "bar" In the expression: do incrementCounter writeFile "foo.txt" "bar" decrementCounter In an equation for ‘someTransaction’: someTransaction = do incrementCounter writeFile "foo.txt" "bar" decrementCounter | 11 | writeFile "foo.txt" "bar" | ^^^^^^^^^^^^^^^^^^^^^^^^^