elisp: Properties in Mode
22.4.6 Properties in the Mode Line
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Certain text properties are meaningful in the mode line. The ‘face’
property affects the appearance of text; the ‘help-echo’ property
associates help strings with the text, and ‘keymap’ can make the text
mouse-sensitive.
There are four ways to specify text properties for text in the mode
line:
1. Put a string with a text property directly into the mode line data
structure.
2. Put a text property on a mode line %-construct such as ‘%12b’; then
the expansion of the %-construct will have that same text property.
3. Use a ‘(:propertize ELT PROPS...)’ construct to give ELT a text
property specified by PROPS.
4. Use a list containing ‘:eval FORM’ in the mode line data structure,
and make FORM evaluate to a string that has a text property.
You can use the ‘keymap’ property to specify a keymap. This keymap
only takes real effect for mouse clicks; binding character keys and
function keys to it has no effect, since it is impossible to move point
into the mode line.
When the mode line refers to a variable which does not have a
non-‘nil’ ‘risky-local-variable’ property, any text properties given or
specified within that variable’s values are ignored. This is because
such properties could otherwise specify functions to be called, and
those functions could come from file local variables.
Info Catalog
elisp: %-Constructs
elisp: Mode Line Format
elisp: Header Lines