xsl: how to tell if a variable has been declared

Question

I have a variable in my xsl that may or may not be declared. How can I tell if it has been declared.

The issue is I have 2 style sheets. A parent (where the global variable is declared) and a child (where the global variable is referenced). I usually call the parent stylesheet which then calls the child stylesheet. So everything is fine because the variable is declared. But I sometimes call the child style sheet by itself.

So the easiest solution for me is a way to check if the variable has been declared before trying to use it.

Any help is greatly appreciated.

Answer 1

This is not necessary.

XSLT is a declarative language. You can't use a stylesheet that has undeclared references, because that is a compile-time error, not a run-time error.

Which means that if the stylesheet compiles at all, it will never run into an "undeclared variable" error by definition.

What are you trying to do?

Answer 2

Assuming your stylesheet is referencing a second sheet where you are not certain of the contents, try xsl:import (as opposed to xsl:include).

Answer 3

In xsl you cannot tell if a variable is declared.

The solution I came up with, was having an interim xsl file that declared the variable and then imported the "child" xsl file.