com.saxonica.bytecode
Class ForExpressionCompiler

java.lang.Object
  com.saxonica.bytecode.ExpressionCompiler
      com.saxonica.bytecode.ToIteratorCompiler
          com.saxonica.bytecode.ForExpressionCompiler

public class ForExpressionCompiler
extends ToIteratorCompiler

Generate bytecode for a call to the ForExpression()

Constructor Summary

ForExpressionCompiler()

Method Summary

void	compileToIterator(CompilerService compiler, Expression expression) Generate bytecode to evaluate the ForExpression as an iterator Precondition: none.
void	compileToLoop(CompilerService compiler, Expression expression, LoopBodyGenerator loopBody) The compileToLoop method compiles this expression in such a way that the code generated by the supplied loopBody argument will be executed once for each item in the result of this expression.
void	compileToPush(CompilerService compiler, Expression expression) Generate bytecode to evaluate the ForExpression in push mode Precondition: none.
static Class	generateSequenceMappingAction(CompilerService compiler, ForExpression expression, Expression action, int slotNumber) Generate a mapping function with a map() method that returns an iterator over the results of one iteration of the loop

Methods inherited from class com.saxonica.bytecode.ToIteratorCompiler

compileToBoolean, compileToItem

Methods inherited from class com.saxonica.bytecode.ExpressionCompiler

allocateStatic, compileItemFromInt, compileItemFromString, compileToPrimitive, generateMethod, getConfiguration, handleEmptyStringResult, setConfiguration, throwXPathException, throwXPathException, unboxItem, verify, visitAnnotation, visitLineNumber

Methods inherited from class java.lang.Object

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

Constructor Detail

ForExpressionCompiler

public ForExpressionCompiler()

Method Detail

compileToPush

public void compileToPush(CompilerService compiler,
                          Expression expression)
                   throws CannotCompileException

Generate bytecode to evaluate the ForExpression in push mode Precondition: none. Postcondition: the stack is empty

Overrides:

compileToPush in class ToIteratorCompiler

Parameters:

compiler - the compiler service

expression - the expression to be compiled

Throws:

CannotCompileException

compileToLoop

public void compileToLoop(CompilerService compiler,
                          Expression expression,
                          LoopBodyGenerator loopBody)
                   throws CannotCompileException

The compileToLoop method compiles this expression in such a way that the code generated by the supplied loopBody argument will be executed once for each item in the result of this expression. The code generated by the loopBody expects to find this item on the top of the bytecode stack.

Overrides:

compileToLoop in class ExpressionCompiler

Parameters:

compiler - the compiler service

expression - the expression to be compiled

loopBody - a generator which produces code to be executed once for every item in the result of this expression, with that item being on the top of the bytecode stack.

Throws:

CannotCompileException

compileToIterator

public void compileToIterator(CompilerService compiler,
                              Expression expression)
                       throws CannotCompileException

Generate bytecode to evaluate the ForExpression as an iterator Precondition: none. Postcondition: the stack contains an iterator representing the result of the expression

Specified by:

compileToIterator in class ExpressionCompiler

Parameters:

compiler - the compiler service

expression - the expression to be compiled

Throws:

CannotCompileException

generateSequenceMappingAction

public static Class generateSequenceMappingAction(CompilerService compiler,
                                                  ForExpression expression,
                                                  Expression action,
                                                  int slotNumber)
                                           throws CannotCompileException

Generate a mapping function with a map() method that returns an iterator over the results of one iteration of the loop

Parameters:

compiler - the CompilerService

expression - the "for" expression itself

action - the body of the "for" loop, which represents the expression to be compiled

Throws:

CannotCompileException