org.basex.query.expr
Class ForLet

java.lang.Object
  org.basex.query.ExprInfo
      org.basex.query.expr.Expr
          org.basex.query.expr.Single
              org.basex.query.expr.ForLet

Direct Known Subclasses:

For, Let

public abstract class ForLet
extends Single

Abstract For/Let Clause.

Author:

Workgroup DBIS, University of Konstanz 2005-10, ISC License, Christian Gruen

Nested Class Summary

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

Expr.Use

Field Summary

Var	var Variable.

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

expr

Method Summary

String	color() Returns a color string for the expression.
boolean	removable(Var v, QueryContext ctx) Checks if the specified variable is removable.
Expr	remove(Var v) Removes the specified variable in a sub expression.
Return	returned(QueryContext ctx) Indicates the return type of an expression.
boolean	uses(Expr.Use u, QueryContext ctx) Indicates if an expression uses the specified type.

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

comp, plan

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

addText, atomic, checkCtx, checkDbl, checkItr, duplicates, e, ebv, i, indexAccessible, indexEquivalent, iter, sameAs, size, test, v

Methods inherited from class org.basex.query.ExprInfo

info, name, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

var

public Var var

Variable.

Method Detail

uses

public final boolean uses(Expr.Use u,
                          QueryContext ctx)

Description copied from class: Expr

Indicates if an expression uses the specified type. Called by the compiler to perform certain optimizations. true is returned by default and thus assumed as "worst-case".

Overrides:

uses in class Single

Parameters:

u - use type to be checked

ctx - query context

Returns:

result of check

removable

public final boolean removable(Var v,
                               QueryContext ctx)

Description copied from class: Expr

Checks if the specified variable is removable.

Overrides:

removable in class Expr

Parameters:

v - variable to be removed

ctx - query context

Returns:

result of check

remove

public final Expr remove(Var v)

Description copied from class: Expr

Removes the specified variable in a sub expression.

Overrides:

remove in class Single

Parameters:

v - variable to be removed

Returns:

expression with removed variable

returned

public final Return returned(QueryContext ctx)

Description copied from class: Expr

Indicates the return type of an expression. Called by the compiler to check if expressions can be reformulated. null is returned by default.

Overrides:

returned in class Expr

Parameters:

ctx - query context

Returns:

result of check

color

public final String color()

Description copied from class: ExprInfo

Returns a color string for the expression.

Overrides:

color in class ExprInfo

Returns:

color