script:walkthrough:exceptions
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| Both sides previous revision Previous revision Next revision | Previous revision | ||
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script:walkthrough:exceptions [2019-11-20 21:16] skyjake [Try and catch] |
script:walkthrough:exceptions [2019-11-20 21:29] skyjake [Catching native errors] |
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| Line 11: | Line 11: | ||
| try: print 'Nothing thrown yet.' | try: print 'Nothing thrown yet.' | ||
| catch: print 'Skipped.' | catch: print 'Skipped.' | ||
| + | |||
| + | ===== Throwing exceptions ===== | ||
| Exceptions are thrown using a ''throw'' statement. | Exceptions are thrown using a ''throw'' statement. | ||
| Line 21: | Line 23: | ||
| print 'Exception caught' | print 'Exception caught' | ||
| end | end | ||
| + | |||
| + | ===== Handling exceptions ===== | ||
| If the exception does not require any handling, one can use ''pass'' as the catch block. | If the exception does not require any handling, one can use ''pass'' as the catch block. | ||
| Line 37: | Line 41: | ||
| Caught: [Error] (in script) OMG! | Caught: [Error] (in script) OMG! | ||
| + | |||
| + | |||
| + | Multiple ''catch'' blocks can be chained together to catch specific types of exceptions. | ||
| + | |||
| + | try | ||
| + | throw 'This will be printed' | ||
| + | | ||
| + | catch NullError: print 'Got NullError' | ||
| + | catch Error, er: print er | ||
| + | catch: print 'Never here.' | ||
| Try/catch can be nested, and an exception thrown in an inner try block can be caught in an outer block. | Try/catch can be nested, and an exception thrown in an inner try block can be caught in an outer block. | ||
| Line 77: | Line 91: | ||
| print 'Fumbled it...' | print 'Fumbled it...' | ||
| end | end | ||
| + | |||
| + | ===== Catching native errors ===== | ||
| Native code may throw various kinds of exceptions that can then be caught in the script. In the example below, a ''NullError'' gets thrown because the code tries to access a deleted object via an alias. | Native code may throw various kinds of exceptions that can then be caught in the script. In the example below, a ''NullError'' gets thrown because the code tries to access a deleted object via an alias. | ||
| Line 88: | Line 104: | ||
| print 'Oh noes:', er | print 'Oh noes:', er | ||
| end | end | ||
| - | |||
| - | Multiple ''catch'' blocks can be chained together to catch specific types of exceptions. | ||
| - | |||
| - | try | ||
| - | throw 'This will be printed' | ||
| - | | ||
| - | catch NullError: print 'Got NullError' | ||
| - | catch Error, er: print er | ||
| - | catch: print 'Never here.' | ||
| ''ReadOnlyError'' is thrown when trying to change a ''const'' variable. | ''ReadOnlyError'' is thrown when trying to change a ''const'' variable. | ||
| Line 112: | Line 119: | ||
| end | end | ||
| + | Any type of native exception can be caught in a script. | ||
script/walkthrough/exceptions.txt ยท Last modified: 2019-11-20 21:29 by skyjake
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