Re: How to fix Emacs24 compiler warning w/o breaking code for previous versions

[Daniel Colascione]

On 6/16/11 8:42 PM, Jambunathan K wrote:
> I was hoping that there is an elisp equivalent for C-like
> 
> #if emacs-version > a
>     do this
> #else
>     do that
> #endif
> 

The Common Lisp #+ reader macro provides the facility you want. For example,

    (progn #+some-feature 42)

would read as

    (progn 42)

on systems with some-feature present and

    (progn)

on systems without that feature.

CL also allows arbitrary combinations of and, or, and not calls, e.g,

    #+(or feature1 (not feature2))

#- also exists, and is similar, except that the sense of the test is
inverted.

Might this feature be worth adding to Emacs? Of course, it would only
help code written for Emacs 24 and above.

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