CODEWITHSUNDEEP
emacsmacroslispelisp
Anycorn
Anycorn

Reputation: 51465

elisp mapcar + lambda + defmacro help

I am trying to generate functions using a macro:

(defmacro make-my-emacs-command-region (cmd name)
  (list 'defun (intern (format "my-emacs-command-%s-%s" cmd name))
        '(&optional arg)
        (list 'interactive "p")
        (list (intern (format "mark-%s" name)) 'arg)
        (list (intern (format "my-emacs-command-%s-region" cmd))
              '(region-beginning) '(region-end))))

generator:

(mapcar (lambda (a) (make-my-emacs-command-region a buffer))
        '(foo bar))

But I get:

my-emacs-command-a-buffer

What am I doing wrong? How can I force to pass value of a?

Upvotes: 5

Views: 876

Answers (2)

Trey Jackson
Trey Jackson

Reputation: 74430

A major point of lisp macros is that the arguments are not evaluated. Read up on the macro pages in the manual, specifically the expansion of macros. The macroexpand function would be of use in debugging the problem. Also, backquote might help you write the body of the macro a little more succinctly.

Upvotes: 7

JB.
JB.

Reputation: 42094

My elisp is a bit rusty, but until someone comes up with the actual explanation: I could get your examples to work a bit more as expected my replacing cmd with (eval cmd) (possibly same with name) in the macro definition body.

Hope this helps.

Upvotes: 4

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