Package it.unive.lisa.symbolic

Class SymbolicExpression

java.lang.Object

it.unive.lisa.symbolic.SymbolicExpression

Direct Known Subclasses:

HeapExpression, ValueExpression

public abstract class SymbolicExpression
extends java.lang.Object

A symbolic expression that can be evaluated by SemanticDomains.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SymbolicExpression(Type staticType, CodeLocation location)	Builds the symbolic expression.

Method Summary

Modifier and Type	Method	Description
abstract <T> T	accept(ExpressionVisitor<T> visitor, java.lang.Object... params)	Accepts an ExpressionVisitor, visiting this expression recursively.
boolean	equals(java.lang.Object obj)
CodeLocation	getCodeLocation()	Yields the code location of the statement that has generated this symbolic expression.
Type	getDynamicType()	Yields the dynamic type of this expression, that is, the most specific common supertype of all its runtime types (available through getRuntimeTypes(TypeSystem).
java.util.Set<Type>	getRuntimeTypes(TypeSystem types)	Yields the runtime types of this expression.
Type	getStaticType()	Yields the static type of this expression.
int	hashCode()
boolean	hasRuntimeTypes()	Yields true if this expression's runtime types have been set (even to the empty set).
abstract SymbolicExpression	popScope(ScopeToken token)	Pops the scope identified by the given token from the expression.
abstract SymbolicExpression	pushScope(ScopeToken token)	Pushes a new scope, identified by the give token, in the expression.
void	setRuntimeTypes(java.util.Set<Type> types)	Sets the runtime types to the given set of types.
abstract java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SymbolicExpression

protected SymbolicExpression(Type staticType,
                             CodeLocation location)

Builds the symbolic expression.

Parameters:

staticType - the static type of this expression

location - the code location of the statement that has generated this expression

Method Detail

getStaticType

public Type getStaticType()

Yields the static type of this expression.

Returns:

the static type

getRuntimeTypes

public final java.util.Set<Type> getRuntimeTypes(TypeSystem types)

Yields the runtime types of this expression. If setRuntimeTypes(Set) has never been called before, this method will return all instances of the static type.

Parameters:

types - the type system that knows about the types of the program point where this method is called. If hasRuntimeTypes() returns true, this parameter can be null

Returns:

the runtime types

setRuntimeTypes

public void setRuntimeTypes(java.util.Set<Type> types)

Sets the runtime types to the given set of types.

Parameters:

types - the runtime types

hasRuntimeTypes

public boolean hasRuntimeTypes()

Yields true if this expression's runtime types have been set (even to the empty set). If this method returns false, then getDynamicType() will yield the same as getStaticType(), and getRuntimeTypes(TypeSystem) returns all possible instances of the static type.

Returns:

whether or not runtime types are set for this expression

getDynamicType

public final Type getDynamicType()

Yields the dynamic type of this expression, that is, the most specific common supertype of all its runtime types (available through getRuntimeTypes(TypeSystem). If setRuntimeTypes(Set) has never been called before, this method will return the static type.

Returns:

the dynamic type of this expression

pushScope

public abstract SymbolicExpression pushScope(ScopeToken token)
                                      throws SemanticException

Pushes a new scope, identified by the give token, in the expression. This causes all Variables to become OutOfScopeIdentifiers associated with the given token.

Parameters:

token - the token identifying the scope to push

Returns:

a copy of this expression where the local variables have gone out of scope

Throws:

SemanticException - if an error occurs during the computation

popScope

public abstract SymbolicExpression popScope(ScopeToken token)
                                     throws SemanticException

Pops the scope identified by the given token from the expression. This causes all the invisible variables (i.e. OutOfScopeIdentifiers) mapped to the given scope to become visible (i.e. Variables) again.

Parameters:

token - the token of the scope to be restored

Returns:

a copy of this expression where the local variables associated with the given scope are visible again

Throws:

SemanticException - if an error occurs during the computation

accept

public abstract <T> T accept(ExpressionVisitor<T> visitor,
                             java.lang.Object... params)
                      throws SemanticException

Accepts an ExpressionVisitor, visiting this expression recursively.

Type Parameters:

T - the type of value produced by the visiting callbacks

Parameters:

visitor - the visitor

params - additional optional parameters to pass to each visiting callback

Returns:

the value produced by the visiting operation

Throws:

SemanticException - if an error occurs during the visiting

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

getCodeLocation

public CodeLocation getCodeLocation()

Yields the code location of the statement that has generated this symbolic expression. The code location is not used for the equality between two symbolic expressions.

Returns:

the code location of the statement that has generated this symbolic expression

toString

public abstract java.lang.String toString()

Overrides:

toString in class java.lang.Object