[xquery-talk] Setting global variables
Ronald Bourret
rpbourret at rpbourret.com
Tue Oct 30 21:55:23 PST 2007
Is there any way to set a global variable from inside a function? (By
"global variable", I mean a variable declared in the prolog of a
function library.)
Basically, I'd like to read a document and save a subset of the document
in a global variable, then refer to it later when doing lookups. For
example, I'd like to do something like the following:
declare variable $foo:listOfNames external;
declare function foo:firstFunctionCalled(...)
{
let $foo:listOfNames := fn:doc("mydoc.xml")//Name
...
};
declare function foo:functionCalledMuchLater(...)
{
...
if ($name = $foo:listOfNames)
...
};
Currently, I pass such information from function to function until it is
finally used. While this works (and some would argue is the correct
style), it has the following drawbacks:
1) It is difficult to follow the information through the chain of functions.
2) It can be confusing to read the intermediate functions, as these
never really use the information.
3) It is brittle when refactoring the intermediate functions. Because
the information is not really used -- it's just passed along -- it is
easy to accidentally drop.
Thanks,
-- Ron
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