is there a way to see the expanded form of a macro?

[gmannerheim]

I have just begun to learn about macros, and it would be really helpful if I could see what the expanded form of a specific macro looks like.
( using Lispworks)

[Kohath]

Sometimes your IDE will provide a context menu option if you right-click on an invocation of the macro. But the most common way is to use macroexpand or macroexpand-1 (see http://clhs.lisp.se/Body/f_mexp_.htm). The link has examples. I really recommend browsing the Common Lisp Hyperspec when you get spare moments, it has everything in standard Common Lisp in it.

[Kohath]

One other thing, I wrote this little helper macro to make expanding macros easy and readable:

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(defmacro mac (form)
  `(pprint (macroexpand-1 ',form)))

The reason it's a macro is so that you don't have to quote the code you copy in (like you have to with macroexpand and macroexpand-1). Used like so:

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(mac (setf (car hi) 5))

which in Corman Lisp would output:

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(COMMON-LISP::%RPLACA HI 5)

[gmannerheim]

Thanks a lot. Very helpful, especially the "mac" macro.

( I had tried macroexpand myself, but obviously used it in a wrong way, like >>> (macroexpand-1 (form)) )

[Kohath]

Cheers, glad I could help. Many times it will be clearer when you know whether you're using a macro or a function (or a special form for that matter). Function calls all have standard evaluation rules, but macros can do what they want with evaluation (like not evaluate code in the case of mac, or evaluate things lots of times like loop). So when you know that macroexpand(-1) is a function, if you want to pass it code, you have to quote it.