Exceptions: Difference between revisions
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→{{header|Phix}}: added syntax colouring the hard way, phix/basics
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=={{header|Phix}}==
{{libheader|Phix/basics}}
Phix provides try/catch and throw statements.
'''Throwing exceptions'''<br>
You can throw any string (on it's own) or any integer, optionally with any (deeply nested) user_data that you like.
<!--<lang Phix>
<span style="color: #008080;">throw<span style="color: #0000FF;">(<span style="color: #008000;">"oh no"<span style="color: #0000FF;">)</span>
<span style="color: #008080;">throw<span style="color: #0000FF;">(<span style="color: #000000;">1<span style="color: #0000FF;">)</span>
<span style="color: #008080;">throw<span style="color: #0000FF;">(<span style="color: #000000;">501<span style="color: #0000FF;">,<span style="color: #0000FF;">{<span style="color: #008000;">"she"<span style="color: #0000FF;">,<span style="color: #000000;">made<span style="color: #0000FF;">[<span style="color: #000000;">me<span style="color: #0000FF;">]<span style="color: #0000FF;">,<span style="color: #000000;">Do<span style="color: #0000FF;">(<span style="color: #000000;">it<span style="color: #0000FF;">)<span style="color: #0000FF;">}<span style="color: #0000FF;">)
'''Catching exceptions'''<br>
There is one and only one non-optional catch clause per try statement. <br>
The variable caught is a sequence, augmented with run-time diagnostics, with whatever was thrown in e[E_CODE] and/or e[E_USER].
<!--<lang Phix>
<span style="color: #008080;">try</span>
<span style="color: #000000;">one_of<span style="color: #0000FF;">(<span style="color: #000000;">these<span style="color: #0000FF;">)</span>
<span style="color: #008080;">catch</span> <span style="color: #000000;">e</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">e<span style="color: #0000FF;">[<span style="color: #000000;">E_CODE<span style="color: #0000FF;">]<span style="color: #0000FF;">=<span style="color: #000000;">501</span> <span style="color: #008080;">then</span>
<span style="color: #7060A8;">puts<span style="color: #0000FF;">(<span style="color: #000000;">1<span style="color: #0000FF;">,<span style="color: #008000;">"that's no excuse!\n"<span style="color: #0000FF;">)</span>
<span style="color: #008080;">else</span>
<span style="color: #008080;">throw<span style="color: #0000FF;">(<span style="color: #000000;">e<span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
▲end try</lang>
<span style="color: #008080;">end</span> <span style="color: #008080;">try
<!--</lang>-->
An uncaught exception terminates the program in error, otherwise control resumes in the catch clause or after the end try,
with no means (apart from some really nasty inline assembly) of resuming any half-finished block of code, and indeed any
call stack entries between a throw and a catch will already have been torn down and thrown away.<br>
Traditionally fatal errors are re-routed via throw() when the presence of an exception handler is detected.<br>
There is no absurdly confusing finally construct
=={{header|PHL}}==
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