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| -rw-r--r-- | doc/manual/exceptions.txt | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/doc/manual/exceptions.txt b/doc/manual/exceptions.txt index e40742e0a..f18ab5635 100644 --- a/doc/manual/exceptions.txt +++ b/doc/manual/exceptions.txt @@ -67,6 +67,41 @@ follows a ``(`` it has to be written as a one liner: let x = (try: parseInt("133a") except: -1) +Except clauses +-------------- + +Within an ``except`` clause, it is possible to use +``getCurrentException`` to retrieve the exception that has been +raised: + +.. code-block:: nim + try: + # ... + except IOError: + let e = getCurrentException() + # Now use "e" + +Note that ``getCurrentException`` always returns a ``ref Exception`` +type. If a variable of the proper type is needed (in the example +above, ``IOError``), one must use an explicit cast: + +.. code-block:: nim + try: + # ... + except IOError: + let e = (ref IOError)(getCurrentException()) + # "e" is now of the proper type + +However, this is seldom needed. The most common case is to extract an +error message from ``e``, and for such situations it is enough to use +``getCurrentExceptionMsg``: + +.. code-block:: nim + try: + # ... + except IOError: + echo "I/O error: " & getCurrentExceptionMsg() + Defer statement --------------- |