Image 1: Jython Shell Window

The Jython shell consists of an output window on the top and an input field on the bottom. The user enters Jython into the input field. When Enter or is pressed the Jython is evaluated and any output is shown in the output window. Note that Enter will only evaluate the field if the field has not been expanded. If your are using multi-line input for your commands, you can evaluate the commands with Shift+Enter.

The entry window can be expanded with the to the right of the command line. When the entry field is expanded, you can enter more than one line of code to be processed at once. When the entry field isn't expanded, you are limited to evaluating one line of code at a time. As an alternative to the button, you can use Ctrl+/ to change between single and multi-line command line structure.

Pressing the "Up" arrow and "Down" arrow in the entry field goes up and down through the history of commands when you are in single-line input. If you are using multi-line input, use Ctrl+P, Ctrl+N to cycle through previously-executed commands.

After a command has been evaluated, the command will be listed above the Evaluate field. To the right of the command, there are two buttons. The button enters the formula back into the Evaluate field without evaluating it. The button reevaluates the previously entered command without having to manually reenter it.

The Jython Shell window includes syntax highlighting, which colors different parts of the text in different colors. For example, strings will be pink and comments specified with a pound symbol (#) will be green. This syntax highlighting is only available in multi-line input mode. When in multi-line input mode, pressing enter will restore the indentation of the previously-entered line. For example, when setting up the addeParms dictionary in the image above, when Enter was pressed after line three, the indentation of four spaces was automatically applied for line four.

Print statements are not needed in the Jython Shell to output information when a single line of code is being evaluated. Below are a couple of examples:

• Command: 2+6
• Output: 8
• Command: layer.getEnhancementTable()
• Output: Inverse Gray shade

Right-clicking in the entry field brings up a menu that allows for:

• Adding an entry from the history.
• Inserting the identifier for a display control type when creating a display.
• Inserting the text of a procedure call from any of the McIDAS-V Jython Library modules. Note: The shell utilities module has a number of useful Jython shell related commands.
• Inserting any of the defined McIDAS-V actions (e.g., Edit color table, Show window, etc.)

All of the menu items in this tool are unique to the Jython Shell.

The File menu has these unique items:

• Save Commands to Jython Library - Saves any entered commands (up to 100 by default) to the User's local Jython Library as a Procedure or as a block of commands if no Procedure name is provided.
• List Saved History - Lists out previously entered commands.
• List Current Variables - Lists all global Jython Variables currently in use.

The Edit menu has these unique items:

• Reset Jython Shell - Removes any saved variables and commands, as well as clears the output window.
• Clear Output Buffer - Removes any text in the output window, but does not remove any variables or commands from the history.
• Auto-select Operands - Causes the Jython shell to analyze every command entered to see if there are references to variables that have not been set. It will bring up the Data Selection dialog to allow you to choose the fields to use.