The Final Solution - Zope

Most of what you've just learned also applies to DTML's other exception-handling construct, the "try-finally" statement. The "try-finally" statement block differs from "try-except-else" in that it merely detects errors; it does not provide for a mechanism to resolve them. It is typically used to ensure that certain statements are always executed when an error (regardless of type) is encountered.

Here's what it looks like:

<dtml-try>
execute this block
<dtml-finally>
execute this block if exceptions 
are generated
</dtml-try>

If an exception is encountered when running the code within the <dtml-try> block, Zope will stop execution at that point; jump to the <dtml-finally> block; execute the statements within it; and then pass the exception upwards, to the parent <dtml-try> block, if one exists, or to the default handler, which terminates the program.

Take a look at the next example to see how this works:

<dtml-try>
<dtml-try><dtml-var CheckThisOut><dtml-except KeyError><b>No value assigned to the variable: <dtml-var error_value><br></b></dtml-try><dtml-finally><i>Goodbye!</i></dtml-try>

Here's the output:

No value assigned to the variable: CheckThisOut
Goodbye!

It's important to note that the code in the <dtml-finally> block - actually part of the outer <dtml-try> block - will be executed even if errors are encountered in the inner <dtml-try> block.

>>> More Zope Articles          >>> More By Harish Kamath, (c) Melonfire

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