[j-devel] abcl: Newbie problem with `read' function

[<pet...@ya...>]

Dear Peter Graves

I've just signed in to this list. Let me first
introduce myself briefly: After being introduced to
programming with procedural languages at the beginning
of my undergraduate studies (Pascal, some Fortran 90
and C), I deeply delved into O-O Programming in my
final years at university, using some Java and a lot
of Eiffel, having the pleasure to work with its
inventor Prof. Betrand Meyer for my diploma thesis. In
my professional carreer as a software engineer, I
started in two light-weight Perl projects and am now
in a really big Java project. In my spare time, I
continue my programming education. After a brief look
at O-O scripting languages like Python and Ruby, I am
now entering the Lisp world. I would like to use J and
ABCL for my studies, mainly because they are free and
I managed to download them and build them from source
without problems (I am working on Windows XP: Although
crazy for ever better programming languages, I just go
with the mainstream regarding the OS...) and because
abcl-jfli seams to give me acces to the Java
libraries, which would make it possible for me to use
a familiar GUI toolkit (Swing) and other libraries if
needed. As far as I can tell so far, you and your few
colleagues are doing a hell of a job on your editor
and language implementation, and I thank you a lot for
it! If I get deeper into it, I might later be able to
give you some help, although it could always only be a
few hours per week as I have a demanding job and a
family life.

First, a general question: Do you have any record of
J's history and original intentions? Was it just to be
an editor first, and the lisp interpreter was a side
product? Or was it to be a lisp environment from the
beginning? And why is the editor implemented in Java?
Where did the Java-Lisp connection originate? A lot of
people I know use emacs or xemacs which I have never
used myself (for languages like Perl, I use UltraEdit,
for Eiffel EiffelStudio, for VB VS and for Java
Eclipse). Is J some kind of an emacs port to java,
with similar configuration and extension possibilities
in Lisp?

Second, a concrete question, maybe a bug report:
(read) doesn't seem to work correctly if it follows a
(format) for a string that is not terminated by a
newline. The following example is taken from David
Touretzky's `COMMON LISP: A gentle intro...':

(defun my-square ()
  (format t "Please type in a number: ")
  (let ((x (read)))
       (format t "The number ~S squared is ~S.~%" x (*
x x))))

It should produce:

> (my-square)
Please type in a number: 7
The number 7 squared is 49.
NIL

but intead produces:

CL-USER(2): (my-square)
7
Please type in a number: The number 7 squared is 49.
NIL
CL-USER(3): 

in abcl. All works well if I put a newline at the end
of the of the first string: 

(format t "Please type in a number: ~%")

CL-USER(4): (my-square)
Please type in a number: 
7
The number 7 squared is 49.
NIL
CL-USER(5): 

But I don't really want a line break there, and as I
take from Touretzky's book (and also from Paul
Graham's `ANSI Common Lisp' which should describe the
standard), it should work without the newline as well.

Is that a bug or am I misunderstanding something here?

Sincerely yours,

Peter Häfliger


	

	
		
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