Re: Can el-search-query-replace replace mapcar with --map ?

[Michael Heerdegen]

Chunyang Xu <mail@xuchunyang.me> writes:

> It gives me:
>
>   (--map
>    (* x x)
>    '(1 2 3))

which is expected, of course.

The transformation you want is not trivial, and there are some
problematic cases when it gets complicated - e.g. when the mapped lambda
uses in its body a local variable with the same name as the argument
variable, like in
  
#+begin_src emacs-lisp
  (lambda (x) (let ((x (1+ x))) (* x x)))
#+end_src

But that should be corner cases in practice.

I would define a helper function to perform the renaming of the lambda
argument into "it" - something like

#+begin_src emacs-lisp
(defun transform-lambda-form-for---map (lambda-form)
  (pcase-let ((`(lambda (,var) . ,body) lambda-form))
    (macroexpand-1
     `(cl-symbol-macrolet ((,var it))
        ,@body))))
#+end_src

and then el-search-query-replace with the rule

#+begin_src emacs-lisp
`(mapcar ,lambda-form ,list)
 ->
`(--map ,(transform-lambda-form-for---map lambda-form) ,list)
#+end_src

Does that work ok for you?


Regards,

Michael.