org.basex.query.flwor

Class Let

java.lang.Object

org.basex.data.ExprInfo

org.basex.query.expr.Expr

org.basex.query.expr.ParseExpr

org.basex.query.expr.Single

org.basex.query.flwor.ForLet

org.basex.query.flwor.Let

public final class Let
extends ForLet

Let clause.

Author:

BaseX Team 2005-12, BSD License, Christian Gruen

Nested Class Summary

Nested classes/interfaces inherited from class org.basex.query.expr.Expr

Expr.Use

Field Summary

Fields inherited from class org.basex.query.flwor.ForLet

var

Fields inherited from class org.basex.query.expr.Single

expr

Fields inherited from class org.basex.query.expr.ParseExpr

info, size, type

Constructor Summary

Constructors

Constructor and Description
Let(InputInfo ii, Expr e, Var v) Constructor.
Let(InputInfo ii, Expr e, Var v, boolean s) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
Let	comp(QueryContext ctx) Compiles and optimizes the expression, assigns data types and cardinalities.
boolean	declares(Var v) Checks if the given variable is declared by this clause.
Iter	iter(QueryContext ctx) Evaluates the expression and returns an iterator on the resulting items.
void	plan(FElem plan) Creates an expression tree.
java.lang.String	toString()
Var[]	vars() Gathers all variables declared by this clause.

Methods inherited from class org.basex.query.flwor.ForLet

uses

Methods inherited from class org.basex.query.expr.Single

count, removable, remove

Methods inherited from class org.basex.query.expr.ParseExpr

checkBln, checkColl, checkCreate, checkCtx, checkDbl, checkDBNode, checkEStr, checkEStr, checkIO, checkItem, checkItr, checkItr, checkMap, checkNode, checkNoEmpty, checkStr, checkType, checkUp, checkUp, checkWrite, compBln, ebv, item, optPre, preEval, size, test, type, value

Methods inherited from class org.basex.query.expr.Expr

addText, compEbv, hasFreeVars, indexAccessible, indexEquivalent, isEmpty, isFunction, isItem, isVacuous, isValue, iterable, markTailCalls, sameAs

Methods inherited from class org.basex.data.ExprInfo

addPlan, addPlan, description, info, planAttr, planElem

Methods inherited from class java.lang.Object

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

Constructor Detail

Let

public Let(InputInfo ii,
   Expr e,
   Var v)

Constructor.

Parameters:

ii - input info

e - variable input

v - variable

Let

public Let(InputInfo ii,
   Expr e,
   Var v,
   boolean s)

Constructor.

Parameters:

ii - input info

e - variable input

v - variable

s - score flag

Method Detail

comp

public Let comp(QueryContext ctx)
         throws QueryException

Description copied from class: Expr

Compiles and optimizes the expression, assigns data types and cardinalities.

Specified by:

comp in class ForLet

Parameters:

ctx - query context

Returns:

optimized expression

Throws:

QueryException - query exception

iter

public Iter iter(QueryContext ctx)

Description copied from class: Expr

Evaluates the expression and returns an iterator on the resulting items. If this method is not overwritten, Expr.item(org.basex.query.QueryContext, org.basex.util.InputInfo) must be implemented by an expression, as it may be called by this method.

Overrides:

iter in class ParseExpr

Parameters:

ctx - query context

Returns:

resulting item

plan

public void plan(FElem plan)

Description copied from class: ExprInfo

Creates an expression tree.

Overrides:

plan in class Single

Parameters:

plan - root element

toString

public java.lang.String toString()

Specified by:

toString in class ExprInfo

declares

public boolean declares(Var v)

Description copied from class: ForLet

Checks if the given variable is declared by this clause.

Specified by:

declares in class ForLet

Parameters:

v - variable

Returns:

declaration flag

vars

public Var[] vars()

Description copied from class: ForLet

Gathers all variables declared by this clause.

Specified by:

vars in class ForLet

Returns:

variables