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java.lang.Object | +--net.sf.saxon.expr.ExpressionTool
This class, ExpressionTool, contains a number of useful static methods for manipulating expressions. Most importantly, it provides the factory method make() for constructing a new expression
Method Summary | |
static int |
allocateSlots(Expression exp,
int nextFree,
SlotManager frame)
Allocate slot numbers to range variables |
static void |
copyLocationInfo(Expression from,
Expression to)
Copy location information (currently the line number and parent) from one expression to another |
static Value |
eagerEvaluate(Expression exp,
XPathContext context)
Evaluate an expression now; lazy evaluation is not permitted in this case |
static boolean |
effectiveBooleanValue(SequenceIterator iterator)
Determine the effective boolean value of a sequence, given an iterator over the sequence |
static javax.xml.transform.SourceLocator |
getLocator(Expression exp)
Get location information for an expression in the form of a SourceLocator |
static java.lang.String |
indent(int level)
Construct indent string, for diagnostic output |
static Value |
lazyEvaluate(Expression exp,
XPathContext context)
Do lazy evaluation of an expression. |
static Expression |
make(java.lang.String expression,
StaticContext env,
int start,
int terminator,
int lineNumber)
Parse an expression. |
static void |
makeParentReferences(Expression top)
Establish the links from subexpressions to their parent expressions, by means of a recursive tree walk. |
static boolean |
markTailFunctionCalls(Expression exp)
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static Expression |
unsorted(Expression exp,
boolean eliminateDuplicates)
Remove unwanted sorting from an expression, at compile time |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Method Detail |
public static Expression make(java.lang.String expression, StaticContext env, int start, int terminator, int lineNumber) throws XPathException
expression
- The expression (as a character string)env
- An object giving information about the compile-time
context of the expressionterminator
- The token that marks the end of this expression; typically
Tokenizer.EOF, but may for example be a right curly bracelineNumber
- the line number of the start of the expression
XPathException
- if the expression contains a static errorpublic static void copyLocationInfo(Expression from, Expression to)
public static void makeParentReferences(Expression top)
public static javax.xml.transform.SourceLocator getLocator(Expression exp)
public static Expression unsorted(Expression exp, boolean eliminateDuplicates) throws XPathException
XPathException
public static Value lazyEvaluate(Expression exp, XPathContext context) throws XPathException
context
- the run-time evaluation context for the expression. If
the expression is not evaluated immediately, then parts of the
context on which the expression depends need to be saved as part of
the Closure
XPathException
- if any error occurs in evaluating the
expressionpublic static Value eagerEvaluate(Expression exp, XPathContext context) throws XPathException
exp
- the expression to be evaluatedcontext
- the run-time evaluation context
XPathException
- if any dynamic error occurs evaluating the
expressionpublic static boolean markTailFunctionCalls(Expression exp)
public static java.lang.String indent(int level)
level
- the indentation level (the number of spaces to return)
public static int allocateSlots(Expression exp, int nextFree, SlotManager frame)
exp
- the expression whose range variables need to have slot numbers assignednextFree
- the next slot number that is available for allocationframe
- a SlotManager object that is used to track the mapping of slot numbers
to variable names for debugging purposes. May be null.
public static boolean effectiveBooleanValue(SequenceIterator iterator) throws XPathException
iterator
- AN iterator over the sequence whose effective boolean value is required
XPathException
- if a dynamic error occurs
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