Package com.saxonica.ee.extfn

Class CompileXPath

java.lang.Object

net.sf.saxon.functions.AbstractFunction

net.sf.saxon.functions.SystemFunction

com.saxonica.ee.extfn.CompileXPath

All Implemented Interfaces:

Callable, Function, GroundedValue, Item, Sequence

public class CompileXPath
extends SystemFunction

This class implements the saxon:compile-XPath() extension function, which is specially-recognized by the system because it needs access to parts of the static context.

The compile-XPath() extension function compiles an XPath expression to a SEF representation. It was originally defined for Saxon-JS to allow free-standing compilation and execution of dynamic XPath expressions in the browser; this is a back-port to Saxon-Java so that the same code can be executed in either environment, which facilitates testing.

Constructor Summary

Constructors

Constructor	Description
CompileXPath()

Method Summary

Modifier and Type	Method	Description
MapItem	call(XPathContext context, Sequence[] arguments)	Evaluate this function call at run-time
static Expression	make(java.lang.String expression, StaticContext env, int start, int terminator, CodeInjector codeInjector, boolean inCatch)	Upgraded from ExpressionTool.make() to permit 'in-catch' conversion of error variables to calls on saxon:dynamic-error-info()

Methods inherited from class net.sf.saxon.functions.SystemFunction

dependsOnContextItem, dynamicCall, equals, export, exportAdditionalArguments, exportAttributes, fixArguments, getArity, getCardinality, getCompilerName, getContextNode, getDescription, getDetails, getErrorCodeForTypeErrors, getFunctionItemType, getFunctionName, getIntegerBounds, getNetCost, getOperandRoles, getRequiredType, getResultItemType, getResultItemType, getRetainedStaticContext, getSpecialProperties, getStaticBaseUriString, getStreamerName, importAttributes, isTrustedResultType, makeCall, makeFunction, makeFunctionCall, makeOptimizedFunctionCall, resultIfEmpty, setArity, setDetails, setRetainedStaticContext, supplyTypeInformation, toShortString, toString, typeCheckCaller

Methods inherited from class net.sf.saxon.functions.AbstractFunction

atomize, deepEquals, effectiveBooleanValue, getAnnotations, getStringValue, getStringValueCS, isArray, isMap, makeNewContext, simplify, typeCheck

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.Function

getGenre

Methods inherited from interface net.sf.saxon.om.GroundedValue

asIterable, concatenate, containsNode, materialize

Methods inherited from interface net.sf.saxon.om.Item

getLength, head, isStreamed, itemAt, iterate, reduce, subsequence

Methods inherited from interface net.sf.saxon.om.Sequence

makeRepeatable

Constructor Detail

CompileXPath

public CompileXPath()

Method Detail

call

public MapItem call(XPathContext context,
                    Sequence[] arguments)
             throws XPathException

Evaluate this function call at run-time

Parameters:

context - The XPath dynamic evaluation context

arguments - The values of the arguments to the function call. Each argument value (which is in general a sequence) is supplied in the form of an iterator over the items in the sequence. If required, the supplied sequence can be materialized by calling, for example, new SequenceExtent(arguments[i]). If the argument is always a singleton, then the single item may be obtained by calling arguments[i].next(). The implementation is not obliged to read all the items in each SequenceIterator if they are not required to compute the result; but if any SequenceIterator is not read to completion, it is good practice to call its close() method.

Returns:

an iterator over the results of the function. If the result is a single item, it can be returned in the form of a SingletonIterator. If the result is an empty sequence, the method should return EmptyIterator.getInstance()

Throws:

XPathException - if a dynamic error occurs during evaluation of the function. The Saxon run-time code will add information about the error location.

make

public static Expression make(java.lang.String expression,
                              StaticContext env,
                              int start,
                              int terminator,
                              CodeInjector codeInjector,
                              boolean inCatch)
                       throws XPathException

Upgraded from ExpressionTool.make() to permit 'in-catch' conversion of error variables to calls on saxon:dynamic-error-info()

Parse an XPath expression. This performs the basic analysis of the expression against the grammar, it binds variable references and function calls to variable definitions and function definitions, and it performs context-independent expression rewriting for optimization purposes.

Parameters:

expression - The expression (as a character string)

env - An object giving information about the compile-time context of the expression

start - position of the first significant character in the expression

terminator - The token that marks the end of this expression; typically Token.EOF, but may for example be a right curly brace

codeInjector - true allows injection of tracing, debugging, or performance monitoring code; null if not required

inCatch - The Xpath is considered to be in the context of an xsl:catch

Returns:

an object of type Expression

Throws:

XPathException - if the expression contains a static error