Add clickable text in read only buffer?

Question

If i have a writable buffer, i can use this to insert hyperlink.

(require 'button)
(insert-button "foo" 'action (lambda (x) (find-file "~/test.py")))

But i have to add clickable text property to a piece of text in read only buffer. I am trying this

(add-text-properties
 1
 50
 '(lambda (x) (find-file "~/test.py")))

But it is throwing this error

Debugger entered--Lisp error: (error "Odd length text property list")

Any suggestion to solve this?

Answer 1

The reason for the error is that you did not use the correct format to add a text property.

quote from manual:

Function: add-text-properties start end props &optional object

The argument props specifies which properties to add. It should have the form of a property list (see Property Lists): a list whose elements include the property names followed alternately by the corresponding values.

However, for your specific problem, emacs has a different command: emacs lisp manual excerpt

The following functions add a button using an overlay (see Overlays) to hold the button properties: Function: make-button beg end &rest properties

This makes a button from beg to end in the current buffer, and returns it.

If you insist on doing it via text properties, see above link for

Function: make-text-button beg end &rest properties

Example code for specific problem:

(make-button 1 50 'action (lambda(x) (find-file "~/test.py")))