GScheme is back. (III)

[Marko Riedel]

The following message is a courtesy copy of an article
that has been posted to comp.lang.scheme as well.


Hi folks,

there were so many bugs in GScheme it wasn't even funny anymore. I
fixed a lot of these and added primitives and examples.

Bugs fixed:

* Multiple documents are now working properly (save, save as, save to,
  close etc.); e.g. the previous version would not give the user a
  chance to review unsaved documents when quitting etc. You need a
  fairly recent version of GNUstep GUI for all of this to work
  properly.
* There is a better error message when a closure is applied to the
  wrong number of arguments. The message includes the symbolic
  argument list of the closure.
* The document window selects the faulty line if you get a parse error
  while you evaluate the document, so you can see immediately where
  the mistake is.
* Converted some internal predicates to inline functions for speed.
* Sometimes you would get mangled output when evaluating files (the
  output would show up before the form being evaluated). Fixed.

These are the new primitives:

* draw-show produces an image window with the data that have
  accumulated and resets the image
* draw-circle draws a circle of a given radius at the current position
  without changing the position
* fill-circle is like draw-circle, but fills the circle
* random outputs a random integer in the interval [0, n) when invoked
  with an integer "n" and a random double in the interval [0, v) when
  invoked with a double "v"

These are the new examples:

* queenspic.scm solves the n-queens problem taking symmetries into
  account and uses fill-circle to draw an image of each solution and
  the board
* random.scm illustrates the usage of random by producing two images
  of randomly placed circles; the first uses random integers and the
  second random doubles
* rcircles.scm draws random circles (outlines and filled ones)

If you are using the GNUstep live CD 0.9.4.2, which can be found here:

   http://www.linuks.mine.nu/gnustep/

then you need to copy libfl.a to /usr/lib -- it is missing for some
reason.

The URL for GScheme is

   http://www.gnustep.it/marko/GScheme/index.html

Best regards,

Marko Riedel

-- 
+------------------------------------------------------------+
| Marko Riedel, EDV Neue Arbeit gGmbH, mriedel@neuearbeit.de |
| http://www.geocities.com/markoriedelde/index.html          |
+------------------------------------------------------------+