Class ActivationRecord

java.lang.Object
  ActivationRecord

All Implemented Interfaces:

Environment

public class ActivationRecord
extends java.lang.Object
implements Environment

An ActivationRecord is an environment in which one new name is bound to some value, while all other names retain the values they have in some pre-existing outer environment, accessed via a nesting link.

Constructor Summary

ActivationRecord(java.lang.String functionName, java.lang.String parameterName, Expression functionBody, Environment nestingLink)
Creates an activation record that binds a name to a value that is a (possibly recursive) function.

ActivationRecord(java.lang.String name, Value value, Environment nestingLink)
Creates an activation record that binds a name to an ordinary value.

Method Summary

Value

get(java.lang.String name) Return the value corresponding to the specified name.

Methods inherited from class java.lang.Object

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

Constructor Detail

ActivationRecord

public ActivationRecord(java.lang.String name,
                        Value value,
                        Environment nestingLink)

Creates an activation record that binds a name to an ordinary value. This is the kind of binding used for ML's "val".

Parameters:

name - the name being bound

value - the value the name is bound to

nestingLink - the environment being augmented

ActivationRecord

public ActivationRecord(java.lang.String functionName,
                        java.lang.String parameterName,
                        Expression functionBody,
                        Environment nestingLink)

Creates an activation record that binds a name to a value that is a (possibly recursive) function. This is the kind of binding used for ML's "fun".

Parameters:

functionName - the name being bound

parameterName - the function's parameter

functionBody - the function's body

nestingLink - the environment being augmented

Method Detail

get

public Value get(java.lang.String name)

Description copied from interface: Environment

Return the value corresponding to the specified name.

Specified by:

get in interface Environment

Parameters:

name - the name to look up

Returns:

the value associated with the name