Exceptions/Catch an exception thrown in a nested call: Difference between revisions
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Uncaught exceptions give information showing where the exception originated through the nested function calls together with the name of the uncaught exception, (U1) to stderr, then quit the running program. |
Uncaught exceptions give information showing where the exception originated through the nested function calls together with the name of the uncaught exception, (U1) to stderr, then quit the running program. |
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=={{header|Ruby}}== |
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Uses a global variable to count the number of calls to baz |
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<lang ruby>def foo |
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begin |
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bar |
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rescue U0 |
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puts "captured exception U0" |
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end |
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end |
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def bar |
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baz |
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end |
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def baz |
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raise $bazcount == 1 ? U0 : U1 |
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end |
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class U0 < Exception |
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end |
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class U1 < Exception |
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end |
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for $bazcount in [1, 2] |
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foo |
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end</lang> |
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<pre>$ ruby nested_calls.rb |
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captured exception U0 |
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nested_calls.rb:14:in `baz': U1 (U1) |
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from nested_calls.rb:10:in `bar' |
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from nested_calls.rb:3:in `foo' |
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from nested_calls.rb:24 |
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from nested_calls.rb:23:in `each' |
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from nested_calls.rb:23</pre> |
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Wait, why does <code>in `each'</code> appear in the stack trace? There's no each in that code. Ruby translates this |
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<lang ruby>for $bazcount in [1, 2] |
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foo |
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end</lang> |
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to this |
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<lang ruby>[1, 2].each {|$bazcount| foo}</lang> |
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=={{header|Tcl}}== |
=={{header|Tcl}}== |
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