Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!psuvax1!husc6!cs.utexas.edu!uunet!mcsun!unido!infbs!tubsibr!neitzel
From: neitzel@tubsibr.uucp (Martin Neitzel)
Newsgroups: comp.lang.apl
Subject: composition of APL expressions
Keywords: software environments, tool of reverse thought?
Message-ID: <1989Aug26.215026.4039@tubsibr.uucp>
Date: 26 Aug 89 21:50:26 GMT
Sender: neitzel@tubsibr.uucp (Martin Neitzel)
Distribution: comp
Organization: TU Braunschweig, Informatik (Bueltenweg), Germany
Lines: 23

I view most expressions as transformations of the right-most argument,
and composing those transformations in reverse order always felt
quite cumbersome to me.

* Has any experience been made regarding APL with a left-to-right
  evaluation?  I guess there must have been some investigations in
  this matter.  Any references?

* How are current APL systems supporting the "editing" of an APL
  expression?  All the systems I have seen only provide a conventional
  line or full screen editor.  Beyond that, none of them was
  specifically tailored to edit and modify APL expressions.  All
  systems were heavily based on cursor movements.  I could image some
  simple history mechanism (see csh(1)) adapted to APL to be
  worthwhile (something like "3 4 \shape !-2").

* Beyond editing, what are systems doing to aid both the composition
  and analysis of expressions?  For example, is there a system that
  tracks the values and shapes of all subexpressions while the whole
  expression is tweaked by the programmer/user at the same time?

							Martin