io.parsingdata.metal.expression.value

Class UnaryValueExpression

java.lang.Object

io.parsingdata.metal.expression.value.UnaryValueExpression

All Implemented Interfaces:

ValueExpression

Direct Known Subclasses:

Len, Neg, Not, Offset

public abstract class UnaryValueExpression
extends Object
implements ValueExpression

Base class for ValueExpressions with one operand.

A UnaryValueExpression implements a ValueExpression that has one operand (a ValueExpression). The operand is first evaluated. If it evaluates to OptionalValue.empty(), the result of the ValueExpression itself will be that as well.

To implement a UnaryValueExpression, only the eval(Value, Environment, Encoding) must be implemented, handling the case of evaluating one value. This base class takes care of evaluating the operand and handling list semantics.

See Also:

BinaryValueExpression

Field Summary

Fields

Modifier and Type	Field and Description
ValueExpression	operand

Constructor Summary

Constructors

Constructor and Description
UnaryValueExpression(ValueExpression operand)

Method Summary

Modifier and Type	Method and Description
ImmutableList<OptionalValue>	eval(Environment environment, Encoding encoding)
abstract OptionalValue	eval(Value value, Environment environment, Encoding encoding)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

operand

public final ValueExpression operand

Constructor Detail

UnaryValueExpression

public UnaryValueExpression(ValueExpression operand)

Method Detail

eval

public ImmutableList<OptionalValue> eval(Environment environment,
                                         Encoding encoding)

Specified by:

eval in interface ValueExpression

eval

public abstract OptionalValue eval(Value value,
                                   Environment environment,
                                   Encoding encoding)

toString

public String toString()

Overrides:

toString in class Object