> For the complete documentation index, see [llms.txt](https://quantitative-algorithms-by-max-h.gitbook.io/predator-trading-system/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://quantitative-algorithms-by-max-h.gitbook.io/predator-trading-system/overview/predator-script-documentation/predator-script/commands/core.md).

# Core

**Command (Abstract Base Class)**

* **Description:** The `Command` class is an abstract base class (ABC) that defines the interface for all commands in the DSL.
* **Constructor Parameters:** None
* **Methods:**
  * `execute(self, data_provider)`: An abstract method that must be implemented by any subclass. This method will act on the command using the provided `data_provider`.

***

**Open\_Command**

Retrieves the opening price of a market instrument for a specified date.

* **Constructor Parameters:**
  * `date (str)`: The date for which the open price is to be fetched.
* **Methods:**
  * `execute(self, data_provider)`: Calls `data_provider.get_open(self.date)` to retrieve the opening price for the specified date.

**Example Usage:**

```python
open_command = OpenCommand(date="2023-09-02")
open_price = open_command.execute(data_provider)
```

***

**High\_Command**

Retrieves the highest price of a market instrument for a specified date.

* **Constructor Parameters:**
  * `date (str)`: The date for which the high price is to be fetched.
* **Methods:**
  * `execute(self, data_provider)`: Calls `data_provider.get_high(self.date)` to retrieve the highest price for the specified date.

**Example Usage:**

```python
high_command = HighCommand(date="2023-09-02")
high_price = high_command.execute(data_provider)
```

***

**Low\_Command**

Retrieves the lowest price of a market instrument for a specified date.

* **Constructor Parameters:**
  * `date (str)`: The date for which the low price is to be fetched.
* **Methods:**
  * `execute(self, data_provider)`: Calls `data_provider.get_low(self.date)` to retrieve the lowest price for the specified date.

**Example Usage:**

```python
low_command = LowCommand(date="2023-09-02")
low_price = low_command.execute(data_provider)
```

***

**Close\_Command**

Retrieves the closing price of a market instrument for a specified date.

* **Constructor Parameters:**
  * `date (str)`: The date for which the close price is to be fetched.
* **Methods:**
  * `execute(self, data_provider)`: Calls `data_provider.get_close(self.date)` to retrieve the closing price for the specified date.

**Example Usage:**

```python
close_command = CloseCommand(date="2023-09-02")
close_price = close_command.execute(data_provider)
```


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