22.4.11 Reading in Edebug

To instrument a form, Edebug first reads the whole form. Edebug replaces the standard Lisp Reader with its own reader that remembers the positions of expressions. This reader is used by the Edebug replacements for eval-region, eval-defun, eval-buffer, and eval-current-buffer.

Another package, cl-read.el, replaces the standard reader with one that understands Common Lisp reader macros. If you use that package, Edebug will automatically load edebug-cl-read.el to provide corresponding reader macros that remember positions of expressions. If you define new reader macros, you will have to define similar reader macros for Edebug.