Maximizing the Editor's Capabilities

Although any text editor can be used to create an IDL program file, the IDL Editor included in the IDL Development Environment contains features that simplify the process of writing IDL code. For example, if you indent a line using the Tab key, the following lines will be indented as well.

If you click the right mouse button while positioned over an editor window, a context menu appears allowing you to quickly access several of the most convenient commands. The context menu changes to display common debugging commands if IDL is running a program. When you create programs in the Editor window, you also have access to the following features:

If a program error or breakpoint is encountered, IDLDE displays the relevant file, opening it if necessary. The line at which the breakpoint or error occurred is marked. See Debugging and Error-Handling for more on IDL's debugging commands.

If you use the IDL Development Environment, files are opened in the IDL Editor by default. On UNIX platforms, you can simplify the process of using another editor; see Creating a Macro to Call a Text Editor in IDL for UNIX for details.

If you have a file open in the IDL Editor and you modify the file using another editor (on any platform), IDL will warn you that the file in the IDL Editor window has changed, and give you a chance to reload the file.

Navigating Among Procedures and Functions

When you open a file in the IDL Editor, all functions and procedures defined in that file are listed in the Functions/Procedures Menu. On Windows, this feature appears as a pull-down menu located on the IDLDE toolbar. On Motif, this menu is accessed through the () button in the upper left corner of the Editor window.

Select a procedure or function from the drop-down list to move the cursor to the beginning of that procedure or function. This is especially useful for navigating large program files containing multiple procedures and functions.

Commenting Blocks of Code

The IDLDE provides methods to quickly comment and uncomment blocks of code lines. To comment or uncomment lines of code, you may either select the lines to be commented/uncommented or you may simply places the cursor somewhere on the desired line. Commenting and uncommenting can be performed using:

Table 2-2: Block Comment Methods

Table 2-2: Block Comment Methods
Method	Description
Toolbar	Click the Comment or Uncomment toolbar items.
Menu	Use the Edit Comment or Edit Uncomment menu items.
Context menu	Right click over a line (or block of selected lines) to display the context menu. Select Comment or Uncomment.

Searching

The IDL Editor window provides a comprehensive search-and-replace mechanism, allowing you to search for occurrences of a text string in one or more open files. See Search Menu for details.

Changing Text Selection Modes (Windows Only)

Under Microsoft Windows, the IDL Editor provides three ways of selecting text: stream mode, line mode, and column mode.

Stream mode selects text in a stream, beginning with the first character selected and ending with the last character, just as if you were reading the text.

Figure 2-2: A selected stream of text.

Figure 2-2: A selected stream of text.

Line mode selects full lines of text.

Figure 2-3: Text selection using Line Mode.

Figure 2-3: Text selection using Line Mode.

Box mode selects text from one screen column to the next. Selecting text in column mode is similar to drawing a rectangle around the text you wish to select.

Figure 2-4: Column Mode Text Selection

Figure 2-4: Column Mode Text Selection

Switch between the three modes by clicking the right mouse button while positioned over an Editor window. Select the "Selection Mode" option to access a pull-down menu with the three text selection modes. The option with a check mark by it is the currently selected text selection mode. If you have text already selected, the selected area will change to reflect the new mode.

Modifying Chromacoding (Windows Only)

The IDL Editor in IDL for Windows supports chromacoding — different types of IDL statements appear in different colors. To change the default colors used for different types of IDL statements, select File

Preferences, and select the Editor tab.

Turning Chromacoding Off

By default, the Windows IDL Editor uses chromacoding. To turn off chromacoding, select File

Preferences, select the Editor tab, and uncheck the Enable colored syntax checkbox. Alternately, you can specify a

Editor Window Keyboard Shortcuts

The IDL Editor window supports a number of useful keyboard shortcuts, described in the following table.

Table 2-3: IDL Editor Window Key Definitions

Table 2-3: IDL Editor Window Key Definitions
Key (Windows)	Key (Motif)	Action
		Move cursor left or right one character, up or down one line.
Ctrl+	Ctrl+B	Move left one word.
Ctrl+	Ctrl+F	Move right one word.
End	Ctrl+E	Move to end of current line.
Home	Ctrl+A or Home	Move to beginning of current line.
Page Down	Page Down	Move to next screen.
Page Up	Page Up	Move to previous screen.
Shift+Tab		Move cursor one tab-stop left.
Ctrl+Home	Ctrl+Home	Move to beginning of file.
Ctrl+End	Ctrl+End	Move to end of file.
	Ctrl+V	Delete word to the left of the cursor.
Ctrl+K		Delete word to the right of the cursor.
	Ctrl+K	Delete everything in the current line to the right of the cursor.
	Ctrl+U	Delete everything in the current line to the left of the cursor.
Delete	Ctrl+D	Delete the next character.
Ctrl+U		Make selected text (or the character to the right of the cursor) lower-case.
Ctrl+Shift+U		Make selected text (or the character to the right of the cursor) upper-case.
Ctrl+Z	Alt+Z	Undo last action.
Ctrl+Y	Alt+Y	Redo last undone action.
Ctrl+X	Alt+X	Cut selection to clipboard.
Ctrl+Shift+Y		Cut line containing cursor to clipboard.
Ctrl+C	Alt+C	Copy selection to clipboard.
Ctrl+V	Alt+V	Paste contents of clipboard at current cursor location.
Ctrl+]		Find matching `(`, `{`, or `[`character.
Tab		Indent highlighted lines one tab-stop right.