Exception clauses

betmatt has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

I have been trying to understand something of what python has to offer.

try:
# Runs first
<code>
except:
# Runs if exception occurs in try block
<code>
else:
# Executes if try block *succeeds*
<code>
finally:
#  This code *always* executes
<code>
[download]

Does anyone here have experience of converting one to another. Python to Perl or visa versa. I would be interested in seeing examples of how these statements would translate between the two languages.

Comment on Exception clauses Download Code

Replies are listed 'Best First'.
Re: Exception clauses by Discipulus (Canon) on Jun 06, 2019 at 09:37 UTC
Hello betmatt you can use Try::Tiny or Syntax::Keyword::Try module. From the synopis of the modules: `use Try::Tiny; # handle errors with a catch handler try { die "foo"; } catch { warn "caught error: $_"; # not $@ }; # or use Syntax::Keyword::Try; sub foo { try { attempt_a_thing(); return "success"; } catch { warn "It failed - $@"; return "failure"; } }` [download] Also look at ModernPerl book in the chapter dedicated to Exceptions. L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l]
Re^2: Exception clauses by bliako (Abbot) on Jun 06, 2019 at 10:24 UTC
Discipulus just to add that there exists a `finally` clause for both modules you mentioned. Here is how to do it with Try::Tiny: `try { try_some_code() } catch { warn "oops: $_" } finally { $x = 'always-executes' };` btw, I was bitten many times by forgetting the last colon and getting all sort of misleading error messages. This is not java!	[reply] [d/l] [select]
Re: Exception clauses by holli (Abbot) on Jun 06, 2019 at 17:09 UTC
Note that even though neither of the aforementioned modules supports an `else`-block you can simulate one. Both modules allow to return a value from the `try`-block. Try::Tiny returns true/false by itself, Syntax::Keyword::Try returns whatever the `try`-block returns (on success). Basically `my $success = try { # Runs first 1; } catch { # Runs if exception occurs in try block } finally { # This code always executes }; if ( $success ) { # Executes if try block succeeds }` [download] holli You can lead your users to water, but alas, you cannot drown them.	[reply] [d/l] [select]