Re: [Chicken-users] unbound variable: or

[John Cowan]

Michele La Monaca scripsit:

> It would be more correct to say that define-macro has not the feature
> set you're interested in, which may or may not be of general interest
> depending on the context.

If you know for sure that nobody but you will use your macro, then
define-macro is fine, but if you expose it to users, you have created a
booby trap that can go off at any time.

> What is worse is that define-macro used to be the lingua franca for
> macros in Scheme.

For a very brief period.  Before 1986 (R2RS) there were very few
Schemes, and only MIT Scheme survives from that time.  After 1991
(R4RS), syntax-rules caught on.  So you are talking about five years in
the 40-year history of Scheme.

> It was 1991 when define-macro was ushered out the standard

Define-macro was never part of any Scheme standard.  Nonetheless, of
the 33 Schemes in my test suite with macros of some kind, all have
syntax-rules, 15 have define-macro (MIT is not one of them), 13 have
syntax-case, 5 have explicit renaming, 2 have syntactic closures, and 1
have explicit renaming.

> form of unity regarding macros. I doubt it never will.

The nearest thing to unity is syntax-case, though several important
implementations don't have it and probably never will.

-- 
John Cowan          http://www.ccil.org/~cowan        address@hidden
I am he that buries his friends alive and drowns them and draws them
alive again from the water. I came from the end of a bag, but no bag
went over me.  I am the friend of bears and the guest of eagles. I am
Ringwinner and Luckwearer; and I am Barrel-rider.  --Bilbo to Smaug