File: cus-edit.el.html

This file implements the code to create and edit customize buffers.

See custom.el.

No commands should have names starting with custom- because that interferes with completion. Use customize- for commands that the user will run with M-x, and Custom- for interactive commands.

The identity of a customize option is represented by a Lisp symbol. The following values are associated with an option.

0. The current value.

   This is the value of the option as seen by "the rest of Emacs".

   Usually extracted by 'default-value', but can be extracted with
   different means if the option symbol has the 'custom-get'
   property. Similarly, set-default (or the 'custom-set' property)
   can set it.

1. The widget value.

   This is the value shown in the widget in a customize buffer.

2. The customized value.

   This is the last value given to the option through customize.

   It is stored in the 'customized-value' property of the option, in a
   cons-cell whose car evaluates to the customized value.

3. The saved value.

   This is last value saved from customize.

   It is stored in the 'saved-value' property of the option, in a
   cons-cell whose car evaluates to the saved value.

4. The standard value.

   This is the value given in the 'defcustom' declaration.

   It is stored in the 'standard-value' property of the option, in a
   cons-cell whose car evaluates to the standard value.

5. The "think" value.

   This is what customize thinks the current value should be.

   This is the customized value, if any such value exists, otherwise
   the saved value, if that exists, and as a last resort the standard
   value.

The reason for storing values unevaluated: This is so you can have values that depend on the environment. For example, you can have a variable that has one value when Emacs is running under a window system, and another value on a tty. Since the evaluation is only done when the variable is first initialized, this is only relevant for the saved (and standard) values, but affect others values for compatibility.

You can see (and modify and save) this unevaluated value by selecting
"Show Saved Lisp Expression" from the Lisp interface. This will
give you the unevaluated saved value, if any, otherwise the unevaluated standard value.

The possible states for a customize widget are:

0. unknown

   The state has not been determined yet.

1. modified

   The widget value is different from the current value.

2. changed

   The current value is different from the "think" value.

3. set

   The "think" value is the customized value.

4. saved

   The "think" value is the saved value.

5. standard

   The "think" value is the standard value.

6. rogue

   There is no standard value. This means that the variable was
   not defined with defcustom, nor handled in cus-start.el. Most
   standard interactive Custom commands do not let you create a
   Custom buffer containing such variables. However, such Custom
   buffers can be created, for instance, by calling
   customize-apropos with a prefix arg or by calling
   customize-option non-interactively.

7. hidden

   There is no widget value.

8. mismatch

   The widget value is not valid member of the :type specified for the
   option.

Defined variables (72)

Defined functions (208)

Defined faces (25)