Exceptions: Difference between revisions
→{{header|langur}}
m (→{{header|Wren}}: Changed to Wren S/H) |
Langurmonkey (talk | contribs) |
||
| (8 intermediate revisions by 5 users not shown) | |||
Line 4:
{{omit from|M4}}
{{omit from|Retro}}
[[Category:Flow control]]
This task is to give an example of an exception handling routine
Line 20 ⟶ 21:
X.try
X.throw SillyError(‘egg’)
X.catch SillyError se
print(se.message)</syntaxhighlight>
Line 1,596 ⟶ 1,597:
A catch causes all the statements preceding it within a block to be the implicit try block.
▲<syntaxhighlight lang="langur"># do something
throw "not a math exception"
catch
if
# change result...
} else {
Line 1,610 ⟶ 1,609:
} else {
# no exception
...▼
An else section on a catch is optional.
=== exception variable ===
An exception variable may be specified, or you can simply use the implicit variable, which is _err
<syntaxhighlight lang="langur">
100 / 0
catch {
if _err
# change result
123
} else {
# rethrow the exception
throw
}
}
<syntaxhighlight lang="langur">
safediv(7, 0) # 0
</syntaxhighlight>
=={{header|Lasso}}==
Line 2,260 ⟶ 2,264:
=={{header|Pascal}}==
See [[Exceptions#Delphi | Delphi]]
=={{header|PascalABC.NET}}==
User defined exceptuin class
<syntaxhighlight lang="delphi">
type MyException = class(Exception) end;
</syntaxhighlight>
Throw an exception
<syntaxhighlight lang="delphi">
raise new MyException;
</syntaxhighlight>
Catch an exception
<syntaxhighlight lang="delphi">
try
except
on e: MyException do
statement
end;
</syntaxhighlight>
=={{header|Perl}}==
Line 3,094 ⟶ 3,120:
An exception is thrown by the ''die'' keyword, which, if not caught, it terminates the program with an appropriate exit code.
<syntaxhighlight lang="ruby">try {
die "I'm dead!"
}
}
▲catch { |type, msg|
▲ say "msg: #{msg}"; # msg: I'm dead! at test.sf line 2.
▲};
say "I'm alive..."
die "Now I'm dead!"
say "Or am I?"
{{out}}
<pre>
Line 3,109 ⟶ 3,134:
msg: I'm dead! at test.sf line 2.
I'm alive...
Now I'm dead! at test.sf line
</pre>
| |||