Name of Emacs Lisp library that provides `with-gensyms' classic macro

Question

I have the feeling that Emacs Lisp macros are written in some different way than Common Lisp macros. This can't be true, but where is all the gensym things? Recently I was writing a macro and I needed to avoid capturing a lexical variable, so I started searching for gensym function. There is no such function! How can a Lisp that has macros don't have gensym? Maybe it's handled differently in Emacs Lisp?

I've found gensym in cl-lib, that's already something. But what I really need is with-gensyms. Do you know where can I find such a macro (third party package is fine if it's in ELPA or MELPA, although it should be built in Emacs by now, I think).

I'm ready to write these eight lines myself, but this sort of thing shouldn't be rewritten every time, IMHO.

---

Edit: to make it clear: I'm searching for a way to get this once and for all, that's a library that contains it that I can depend upon. If you think it's OK to rewrite it everywhere every time developer needs it -- that's your point of view. If you vote to close the question simply because there is no such library and

Lisp hackers generally do what is practical for them, such as writing a small utility macro and leaving it at that

-- I think your reasoning is fallacious. Lisp hackers generally don't like to redo something simply because that's how people do it. They create what they need and then use it everywhere.

There are quite a few different libraries that make life easier, and they often do more trivial things. Yet when I ask for something that's useful but missing I get this typical answer "well, don't you know, just copy paste it from Goggle because it isn't there".

You can of course close this question, but IMHO it's normal question asking for certain tool that Emacs Lisp developer might find useful in some cases. If you don't know decent solution, that doesn't mean that the question is bad.

Answer 1

Take a look at Missing Macro Tools. It's available on MELPA.

The package provides the following classics:

• mmt-gensym
• mmt-make-gensym-list
• mmt-with-gensyms
• mmt-with-unique-names
• mmt-once-only

Answer 2

In my personal libraries, I also prefer to maintain a connection with Common Lisp idioms and syntax as much as possible, to avoid context switching. Of course, if I would develop public libraries I would try to avoid it. Common Lisp perspective seems not favoured by main Emacs developers, although I know a few representative ones that do favour cl-lib parlance.

In any case, I use el-get to manage the external packages. el-get allows to fecth directly from EmacsWiki. I have this in my init.el:

(el-get-bundle macro-utils)

Which nicely allows one to use with-gensyms, as you asked, and also once-only:

(defmacro double (x)
  (once-only (x)
    `(+ ,x ,x)))

Answer 3

Your question appears to be only "Where can I find with-gensyms?" If so, it should probably be closed, and in any case you seem to now have the answer, from Google.

As to the Emacs-Lisp way of doing things, the answer is make-symbol.

And in fact, org-with-gensyms, which you mention, just uses make-symbol:

(defmacro org-with-gensyms (symbols &rest body)
  `(let ,(mapcar (lambda (s)
                   `(,s (make-symbol (concat "--" (symbol-name ',s))))) symbols)
     ,@body))