feat(symbol): add symbol FunctionTable to store the table of a function

src/decaf/symbol/FunctionTable.java

+package decaf.symbol;
+
+import java.util.*;
+
+import decaf.scope.ClassScope;
+import decaf.type.FuncType;
+
+public class FunctionTable extends Symbol {
+
+	private List<Function> functions;
+
+	public FunctionTable (String name) {
+		this.name = name;
+
+		functions = new ArrayList<Function>();
+	}
+
+	public void appendFunction(Function func) {
+		functions.add(func);
+	}
+
+	/**
+	 * @return the functions
+	 */
+	public List<Function> getFunctions() {
+		return functions;
+	}
+
+	@Override
+	public ClassScope getScope() {
+		return (ClassScope) definedIn;
+	}
+
+	@Override
+	public FuncType getType() {
+		return null;
+	}
+
+	@Override
+	public boolean isFunction() {
+		return false;
+	}
+
+	@Override
+	public boolean isFunctionTable() {
+		return true;
+	}
+
+	@Override
+	public String toString() {
+		return "";
+	}
+
+	@Override
+	public boolean isClass() {
+		return false;
+	}
+
+	@Override
+	public boolean isVariable() {
+		return false;
+	}
+
+}

src/decaf/symbol/Symbol.java

@@ -73,5 +73,10 @@ public abstract class Symbol {
 
 	public abstract boolean isFunction();
 
+	public boolean isFunctionTable()
+	{
+		return false;
+	}
+
 	public abstract String toString();
 }