init commit

archive/design pattern/interpreter.cpp

@@ -0,0 +1,104 @@
+#include <iostream>
+using namespace std;
+
+//expression=command';'*
+//command=action object 'from' databse 'to' database
+//action='copy'|'move'
+//object='view'|'table' name
+//database=string
+class AbstractExpression
+{
+public:
+    virtual string interpert() = 0;
+};
+
+class Object : public AbstractExpression
+{
+    string str;
+
+public:
+    Object(string str)
+    {
+        this->str=str;
+    }
+    string interpert()
+    {
+        if (str.substr(0, 4) == "view")
+        {
+            return "视图";
+        }
+        else
+        {
+            return "表" + str.substr(6);
+        }
+    }
+};
+
+class Database : public AbstractExpression
+{
+    string db;
+
+public:
+    Database(string db)
+    {
+        this->db = db;
+    }
+    string interpert()
+    {
+        return db;
+    }
+};
+
+class Action : public AbstractExpression
+{
+    string action;
+
+public:
+    Action(string action)
+    {
+        this->action = action;
+    }
+    string interpert()
+    {
+        if (action == "copy")
+        {
+            return "复制";
+        }
+        else
+        {
+            return "移动";
+        }
+    }
+};
+
+class Command : public AbstractExpression
+{
+    AbstractExpression *action;
+    AbstractExpression *object;
+    AbstractExpression *db1;
+    AbstractExpression *db2;
+
+public:
+    Command(AbstractExpression *action,
+            AbstractExpression *object,
+            AbstractExpression *db1,
+            AbstractExpression *db2)
+    {
+        this->action = action;
+        this->object = object;
+        this->db1 = db1;
+        this->db2 = db2;
+    }
+    string interpert()
+    {
+        return "从" + db1->interpert() + "中" + action->interpert() + object->interpert() + "到" + db2->interpert();
+    }
+};
+
+int main()
+{
+    string cmd = "copy view from db1 to db2;move table a from db1 to db2;";
+    AbstractExpression *exp = new Command(new Action("copy"), new Object("view"), new Database("db1"), new Database("db2"));
+    cout << exp->interpert() << endl;
+    return 0;
+}