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Environment.java
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Environment.java
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import java.util.ArrayList;
public class Environment<K, V> {
private ArrayList<EnvEntry<K, V>> symbolTables = new ArrayList<EnvEntry<K, V>>();
public String toString() {
return String.format("%s", symbolTables);
}
public void beginScope() {
symbolTables.add(new EnvEntry<K, V>(EnvEntryType.BEGIN_SCOPE));
}
public void endScope() {
symbolTables.add(new EnvEntry<K, V>(EnvEntryType.END_SCOPE));
}
public void add(K key, V value) {
symbolTables.add(new EnvEntry<K, V>(key, value));
}
public V lookup(K key) {
for (int i = symbolTables.size() - 1; i >= 0; i--) {
K symbolKey = symbolTables.get(i).key;
if (symbolKey != null && symbolKey.equals(key)) {
return symbolTables.get(i).value;
}
}
return null;
}
public V lookupInScope(K key) {
for (int i = symbolTables.size() - 1; i >= 0; i--) {
EnvEntry<K, V> entry = symbolTables.get(i);
if (entry.type == EnvEntryType.BEGIN_SCOPE) {
break;
}
if (entry.key != null && entry.key.equals(key)) {
return symbolTables.get(i).value;
}
}
return null;
}
}