A form consists of read only text for documentation and some fields, where each field contains two parts, a tag and a value. The tags are used to identify the fields, so the documentation can refer to the ‘foo field’, meaning the field tagged with ‘Foo’. Here is an example form:
Here is some documentation. Name: My Name Choose: This option Address: Some Place In some City Some country. See also _other work_ for more information. Numbers: count to three below [INS] [DEL] One [INS] [DEL] Eh, two? [INS] [DEL] Five! [INS] Select multiple: [X] This [ ] That [X] Thus Select one: (*) One ( ) Another One. ( ) A Final One. [Apply Form] [Reset Form]
The top level widgets in this example are tagged ‘Name’, ‘Choose’, ‘Address’, ‘_other work_’, ‘Numbers’, ‘Select multiple’, ‘Select one’, ‘[Apply Form]’, and ‘[Reset Form]’. There are basically two things the user can do within a form, namely editing the editable text fields and activating the buttons.
In the example, the value for the ‘Name’ is most likely displayed in an editable text field, and so are values for each of the members of the ‘Numbers’ list. All the normal Emacs editing operations are available for editing these fields. The only restriction is that each change you make must be contained within a single editable text field. For example, capitalizing all text from the middle of one field to the middle of another field is prohibited.
Editable text fields are created by the
Warning: In an
editable-field widget, the editable
field must not be adjacent to another widget—that won't work.
You must put some text in between. Either make this text part of
editable-field widget itself, or insert it with
:format keyword is useful for generating the necessary
text; for instance, if you give it a value of
"Name: %v ",
the ‘Name: ’ part will provide the necessary separating text
before the field and the trailing space will provide the
separating text after the field. If you don't include the
:size keyword, the field will extend to the end of the
line, and the terminating newline will provide separation after.
Warning: In an
editable-field widget, the ‘%v’ escape
must be preceded by some other text in the
The editing text fields are highlighted with the
widget-field-face face, making them easy to find.
Some portions of the buffer have an associated action, which can be invoked by a standard key or mouse command. These portions are called buttons. The default commands for activating a button are:
Invoke the button at pos, defaulting to point. If point is not located on a button, invoke the binding in
widget-global-map(by default the global map).
There are several different kind of buttons, all of which are present in the example:
menu-choicewidget. In the example, ‘Choose’ is an option field tag.
radio-button-choicewidget can be selected at any time. When you invoke one of the unselected radio buttons, it will be selected and the previous selected radio button will become unselected.
push-buttonwidget. The main difference from the
linkwidget is that the buttons will be displayed as GUI buttons when possible.
To make them easier to locate, buttons are emphasized in the buffer.
Face used for highlighting a button when the mouse pointer moves across it.
You can use all the normal Emacs commands to move around in a form buffer, plus you will have these additional commands: