So I meant to ask which processors don't always evaluate f(x) to find
out that it's y, never remembering that f(x) *is* y for subsequent
calls. For extension functions, people often count on the evaluation
having side-effects or returning different results, so I'm interested to
know which processors will catch these people off-guard. I think XT
might be one of them, IIRC.
Saxon 7.x has an extension that allows you to request memoisation of
stylesheet functions
<xsl:function name="f" saxon:memo-function="yes">
This only works for stylesheet functions, but you can always wrap a
stylesheet function around an external extension function.
It's not the default, because I suspect there would be many cases where
you would just use a lot of memory and gain no benefit.
Michael Kay
Software AG
home: Michael(_dot_)H(_dot_)Kay(_at_)ntlworld(_dot_)com
work: Michael(_dot_)Kay(_at_)softwareag(_dot_)com
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