Re: Package problem, revisted

[cox@Franz.COM (Charles A. Cox)]

> Date: Wed, 19 Aug 1992 18:01:10 GMT
> From: Barry Margolin <barmar@Think.COM>
> 
>     Date: Wed, 19 Aug 1992 11:35 EDT
>     From: qobi@unagi.cis.upenn.edu
> 
>     I used to use symbols to refer to packages until I ran into the aforementioned
>     difficulties. Then I switched to using strings. But this too has its problems.
>     CommonLisp systems differ as to whether they use upper or lower case for
>     package names (much in the same way as the case of symbol print names can
>     differ). So I ran into problems trying to make a program portable across
>     numerous CommonLisp implementations. That was about three years ago and I
>     don't remember the exact details nor which was the offending implementation.
>     (I think it was Allegro on NeXT or some derivative of KCL/AKCL/IBCL).
> 
> It was almost certainly Allegro CL.  It has a number of features that
> allow it to handle default-lowercase and case-sensitive input,
> presumably intended to make porting Franz Lisp programs easier.

  Allegro CL has long had a non-standard extension which allows the
reader to be case-sensitive and further to store the symbol-names of
all the initial Common Lisp symbols in lower-case.  Normally, the
default is to have this feature turned off so that the reader follows
standard Common Lisp case-insensitive-upper-preferred behavior.  For
the NeXT, however, Allegro CL's default reader behavior is
case-sensitive-lower-preferred.  The reason for making the NeXT ACL a
special case was that it made the interface to Objective-C a lot
easier to use.  The reader behavior, however, can be changed at ACL
install-time or at ACL run-time.

  I believe that this default NeXT Allegro CL non-standard reader
behavior was prominently documented, although I don't know how obvious
it might have been to a casual user of NeXT Allegro CL.

	Charley
---
Charles A. Cox, Franz Inc.        1995 University Avenue, Suite 275
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