net.sourceforge.czt.animation.eval.flatpred

Class FlatBinding

java.lang.Object

net.sourceforge.czt.animation.eval.flatpred.FlatPred

net.sourceforge.czt.animation.eval.flatpred.FlatBinding

public class FlatBinding
extends FlatPred

Evaluates ZBinding terms. It implements <| name1==e1, name2==e2, ... nameN==eN |> = bind. Note that this is similar to the theta operator in Z, which explodes bind (a ZBinding term) into a set of names and expressions.

Author:

leo, marku (Rewrote nextEvaluation, 3 Feb 2006)

Field Summary

Fields

Modifier and Type	Field and Description
protected net.sourceforge.czt.z.util.Factory	factory_

Fields inherited from class net.sourceforge.czt.animation.eval.flatpred.FlatPred

args_, evalMode_, freeVars_, INDENT, LOG, printer_, solutionsReturned_

Constructor Summary

Constructors

Constructor and Description
FlatBinding(List<net.sourceforge.czt.z.ast.ZName> names, List<net.sourceforge.czt.z.ast.ZName> exprs, net.sourceforge.czt.z.ast.ZName bind) Constructs a FlatBinding FlatPred.

Method Summary

Modifier and Type	Method and Description
<R> R	accept(net.sourceforge.czt.util.Visitor<R> visitor) Calls visitor.visitPred (preferably) or visitor.visitTerm.
Mode	chooseMode(Envir env) Same modes as FlatTuple
boolean	inferBounds(Bounds bnds) Infer bounds for any integer variables.
boolean	nextEvaluation() Generates the next solution that satisfies this predicate.
String	toString() A default implementation of toString.

Methods inherited from class net.sourceforge.czt.animation.eval.flatpred.FlatPred

freeVars, getArgs, getEnvir, getLastArg, getMode, indent, modeAllDefined, modeCollection, modeFunction, modeOneOutput, printArg, printBinOp, printLastArg, printName, printQuant, setMode, startEvaluation

Methods inherited from class java.lang.Object

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

Field Detail

factory_

protected net.sourceforge.czt.z.util.Factory factory_

Constructor Detail

FlatBinding

public FlatBinding(List<net.sourceforge.czt.z.ast.ZName> names,
                   List<net.sourceforge.czt.z.ast.ZName> exprs,
                   net.sourceforge.czt.z.ast.ZName bind)

Constructs a FlatBinding FlatPred.

Parameters:

names - The list of names in the binding (name1,name2,...nameN). (no duplicates)

exprs - The list of expressions (e1,e2,...,eN).

bind - The name of the BindExpr \lblot name1==e1, ... nameN==eN \rblot.

Method Detail

inferBounds

public boolean inferBounds(Bounds bnds)

Description copied from class: FlatPred

Infer bounds for any integer variables. This analyzes the possible range of values of each integer variable used by this FlatPred, and reduces the range of values if possible. This is a kind of static analysis commonly used in constraint solvers (bounds consistency). For example, if y already has the range 10..20, then the FlatPred x < y would set the maximum value of x to 19.

Overrides:

inferBounds in class FlatPred

Parameters:

bnds - The database of lower and upper bounds for integer variables.

Returns:

true iff the bnds database has been changed.

The default implementation infers nothing and returns false.

chooseMode

public Mode chooseMode(Envir env)

Same modes as FlatTuple

Specified by:

chooseMode in class FlatPred

Returns:

The Mode object, with statistics and an updated environment.

nextEvaluation

public boolean nextEvaluation()

Description copied from class: FlatPred

Generates the next solution that satisfies this predicate. This must only be called after startEvaluation().

Specified by:

nextEvaluation in class FlatPred

Returns:

true iff another solution has been found.

toString

public String toString()

Description copied from class: FlatPred

A default implementation of toString. This returns "FlatXXX(args[0], args[1], ...)".

Overrides:

toString in class FlatPred

accept

public <R> R accept(net.sourceforge.czt.util.Visitor<R> visitor)

Description copied from class: FlatPred

Calls visitor.visitPred (preferably) or visitor.visitTerm. Subclasses that correspond to particular kinds of Pred should override this to call more specific visitXXX methods (and should call super to handle the remaining cases).

Overrides:

accept in class FlatPred