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java.lang.Objectjsint.LexicalEnvironment
public class LexicalEnvironment
Environments store mappings from symbols to locations. At compile time, we can lookup to see if a symbol names a location, and at run time we can get or set the value in a location.
Field Summary | |
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static LexicalEnvironment |
NULLENV
The global environment. |
Constructor Summary | |
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LexicalEnvironment(java.lang.Object vars,
java.lang.Object[] vals,
LexicalEnvironment parent)
Create an LexicalEnvironment with local variables and values, and a parent LexicalEnvironment. |
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LexicalEnvironment(java.lang.Object vars,
java.lang.Object[] vals,
LexicalEnvironment parent,
boolean isNullEnv)
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Method Summary | |
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java.lang.Object |
get(LocalVariable var)
Get the value of the LocalVariable in this LexicalEnvironment. |
LocalVariable |
lookup(Symbol var)
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LocalVariable |
lookup(Symbol var,
int up,
int in,
java.lang.Object vars)
Lookup the symbol in the environment. |
java.lang.Object |
set(LocalVariable var,
java.lang.Object newVal)
Set the value of the LocalVariable in this LexicalEnvironment to a new value. |
void |
show(java.io.PrintWriter s)
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java.lang.String |
toString()
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Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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public static final LexicalEnvironment NULLENV
Constructor Detail |
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public LexicalEnvironment(java.lang.Object vars, java.lang.Object[] vals, LexicalEnvironment parent)
public LexicalEnvironment(java.lang.Object vars, java.lang.Object[] vals, LexicalEnvironment parent, boolean isNullEnv)
Method Detail |
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public LocalVariable lookup(Symbol var)
public LocalVariable lookup(Symbol var, int up, int in, java.lang.Object vars)
public java.lang.Object get(LocalVariable var)
public java.lang.Object set(LocalVariable var, java.lang.Object newVal)
public java.lang.String toString()
toString
in class java.lang.Object
public void show(java.io.PrintWriter s)
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