IDLE rapid guide
================

The Idel IDE provides us with two main tools:

- The interpreter or **shell** that allows us to execute Python code  by typing it. The result is shown immediately.

- The **editor window** is the window that allows us to edit our Python code (be it a main program  or one or several functions) and save it into a file. The editor also allow us to execute (or run) the code of the open file anytime.


Executing IDLE
--------------

To execute IDLE simply call the ``idle`` application from the application manager.

Alternatively you can call it from the terminal:

.. code:: bash

          $ idle &

The ``&`` is an option that launches idel while keeping the terminal running in parallel.

Firstly, the Python shell is launched with the promp '>>>' that allows you to type any Python code.


Editing with Idle
-----------------

The editor can be launched to create a new python file or to edit an existing file (``File/Open``).

Once you are done, close IDLE selecting the ``File/Exit`` menu option.

The first time we work with a file we have to give a name to it.

.. warning ::
   
   If the ``Python files *.py, *.pyw)`` option is selected in the drop-down menu ``Files of type``, it will not be necessary to add the extension ``.py`` at the end of the filename to indicate that it contains Python code, because IDLE will do it automatically.
   
.. warning ::

   A file name must only contain one dot separating the name and the extension ``py``.

To open an existing file we have to select the menu option ``File/Open`` and a dialog will be displayed that will allow us to select the file to open or browse other directories to find it.

When we finish working with a file, it is advisable to close the window before opening another one with the ``File/Close`` menu option or directly with the ``'X'`` button.


Program and functions execution
-------------------------------

You can execute the code of the file by:

- 1.- Openning it ith the editor.
- 2.- Select the ``Run/Run Module`` menu option. The code is executed and the result is shown in the shell window.

To execute a function, we select the ``Run/Run Module`` menu option
from the editor window where this function is located. If the
following message appears, it means that the function has been
imported and a reset of the shell has been made.

.. code:: bash
 
          >>> ============== RESTART ==============
          >>> 
          >>>

Once imported, we can execute the function by simply calling it with its name and the values we want to use as parameters.

If we try to run ``Run Module`` and some new code has not been saved, IDLE will ask us if we want to save it before importing it. If we answer ``OK``, first the code will be saved and then the function imported. Conversely, if we answer ``Cancel``, we will return to the editor window and the function will not be imported.

When we import a Python function IDLE can detect syntax errors. In
this case, IDLE will indicate it with a red message within the editor
window.

.. warning::
   
   We have to repeat the previous steps whenever we modify the code of a function in the editor window.
   

Doctests execution with IDLE
----------------------------

See exercise :doc:`temes/test/Doctest_idle/index`


Other aspects
-------------

We have to define a working directory for each lab session and save in it all the related files: files with Python code, testfiles and data files.

To recover previous IDLE commands we can use the key combinations ``ALT-p`` and ``ALT-n``.