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## 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 2005-09, ISC 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.expr.Single
`expr`

Constructor Summary
`ForLet(Expr e, Var v)` Constructor.

Method Summary
`java.lang.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` | `shadows(Var v)` Checks if the specified is not shadowed by another variable.
`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`

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`

Constructor Detail

### ForLet

    public ForLet(Expr e,
                  Var v)

  Constructor.

  Parameters:
    `e` - variable input
    `v` - variable

Method Detail

### uses

    public 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 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 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

### shadows

    public boolean shadows(Var v)

  Checks if the specified is not shadowed by another variable.

  Parameters:
    `v` - variable to be checked
  Returns:
    result of check

### color

    public final java.lang.String color()

  Description copied from class: `ExprInfo`
  Returns a color string for the expression.

  Overrides:
    `color` in class `ExprInfo`
  Returns:
    color

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