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Bug #4222

Updated by Michael Kay over 2 years ago

The XSLT 3,0 spec makes confusingly inconsistent statements about the visibility of global parameters.

* The grammar for `xsl:param` does not allow a `visibility` attribute

* In §3.5.3.1, under `xsl:expose`, we say "The visibility of a variable declared using an `xsl:param` element is always public."

* §9.6 (Static parameters) says: "When the static attribute [of `xsl:param`] is present with the value yes, the visibility attribute must not have a value other than `private`." private." But in fact, no visibility attribute is allowed by the grammar. It is clear in this section that the intent is for static parameters to always be private: there is a note explaining why (specifically, so they cannot be overridden, which is necessary to allow separate compilation of packages; however, I don't see why visibility="final" can't be allowed, which would achieve the same aim.

I think one aspect of this that the spec fails to address is: when package P "uses" package Q, it is presumably using a version of Q whose static parameters have been bound to particular values. But there is no way for P to say what these values should be. There can be two compiled instances of Q with different values bound to the static parameters, and the effect of using these two instances is likely to be quite different.
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