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Re: Eval keymapp in a macros


From: Stefan Monnier
Subject: Re: Eval keymapp in a macros
Date: Thu, 05 Aug 2021 09:53:16 -0400
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux)

> (defmacro with-key-map (mapname &rest body)
>   `(let ((map (eval-and-compile (if (string-match-p "-map$" (symbol-name 
> ',mapname))
>                                   (symbol-name ',mapname)
>                                 (concat (symbol-name ',mapname) "-map"))))
>        (defs '(,@body)))
>      (dolist (def defs)
>        (define-key (symbol-value (intern map))
>        (if (vectorp (car def)) (car def)
>          (read-kbd-macro (car def)))
>          (cdr def)))))

Your `map` variable above has a misleading name since it won't hold
a map but a string (the name of the variable holding the map, so you
need the "double indirection" thought `intern` first and `symbol-value`
afterwards to get at the map).

    (defun my--with-key-map (map defs)
      (dolist (def defs)
        (let ((key (car def)))
          (define-key map
                      (if (vectorp key) key (read-kbd-macro key))
                      (cdr def)))))
    
    (defmacro my-with-key-map (mapname &rest body)
      `(my--with-key-map ,(if (string-match-p "-map\\'" (symbol-name mapname))
                              mapname
                            (intern (format "%s-map" mapname)))
                         ',body))

Look ma!  No `eval-and-compile` and no `symbol-value`.


        Stefan


PS: Personally I'd recommend against the `string-match-p` dance, since
    all it saves you is the typing of `-map` but in exchange it prevents
    you from using your macro with keymaps that have a name that doesn't
    end in `-map` and it "obfuscates" the code a little, preventing
    things like ElDoc and Xref from understanding what's going on.




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