| java.lang.Object
 net.sf.saxon.expr.ComputedExpression
net.sf.saxon.sort.TupleExpression
| TupleExpression | | public class TupleExpression extends ComputedExpression (Code) | | A tuple expression is an expression that returns a tuple. Specifically,
it is a list of n expressions, which are evaluated to create a list of n items.
Tuple expressions are used during the evaluation of a FLWR expression. A tuple
is not a value within the XPath/XQuery type system, so it is represented as
an external object, specifically as a Java array wrapped inside an ObjectValue.
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| TupleExpression | | public TupleExpression(int width)(Code) | | |
| computeCardinality | | public int computeCardinality()(Code) | | Get the cardinality of the expression. This is exactly one, in the sense
that evaluating the TupleExpression returns a single tuple.
the static cardinality - EXACTLY_ONE |
| getIntrinsicDependencies | | public int getIntrinsicDependencies()(Code) | | |
| optimize | | public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException(Code) | | Perform optimisation of an expression and its subexpressions.
This method is called after all references to functions and variables have been resolved
to the declaration of the function or variable, and after all type checking has been done.
Parameters:
opt - the optimizer in use. This provides access to supporting functions; it also allowsdifferent optimization strategies to be used in different circumstances.
Parameters:
env - the static context of the expression
Parameters:
contextItemType - the static type of "." at the point where this expression is invoked.The parameter is set to null if it is known statically that the context item will be undefined.If the type of the context item is not known statically, the argument is set tonet.sf.saxon.type.Type.ITEM_TYPE the original expression, rewritten if appropriate to optimize execution
throws:
net.sf.saxon.trans.StaticError - if an error is discovered during this phase(typically a type error) |
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