Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!ncar!tank!uxc.cso.uiuc.edu!uxc.cso.uiuc.edu!ux1.cso.uiuc.edu!uicsrd.csrd.uiuc.edu!jaxon
From: jaxon@uicsrd.csrd.uiuc.edu
Newsgroups: comp.lang.apl
Subject: Re: APL Novice Looking fer Wisdom
Message-ID: <49700015@uicsrd.csrd.uiuc.edu>
Date: 25 Sep 89 17:41:00 GMT
References: <5509@tank.uchicago.edu>
Lines: 62
Nf-ID: #R:tank.uchicago.edu:5509:uicsrd.csrd.uiuc.edu:49700015:000:3143
Nf-From: uicsrd.csrd.uiuc.edu!jaxon    Sep 25 12:41:00 1989


> 1. Versions / Standards of APL: briefly, what are the significant
>    difference between ANSI/BSI/ISO Standard APL, APL2, and ``Dictionary
>    APL''?

Briefly: ISO describes 'flat' arrays of uniform type elements and operators
that take only the built-in dyadic scalar functions.  The others are competing
definitions with 'nested' arrays of mixed element types where operators can
take any function and (in APL2) users can define operators.  

> 2. Is there any standard for the stored format of APL workspaces?

There is a recognized 'convention' for workspace interchange.  Many APLs have
provided this as the )IN and )OUT commands, or as an application workspace.
It is not efficient enough for everyday use as )LOAD and )SAVE, the format
does not permit random access such as is needed for )COPY.  

With this and all your standards questions, definitive answers can be found
in the ISO APL standard document itself.  ANS required the X3J10 committee to
list there all other standards with which their's interacts.  I don't know
the document number on the last public version, perhaps Lee Dickey will
respond here also (ljdickey@water.waterloo.edu knows these things).

> 3. Is there any standard for the APL character set?

Their graphic appearences are registered with ISO.  The idea of forming new
characters by overstrikes is mentioned in the standard, and a minimum set of
useable characters is prescribed in ISO APL.
  
   Their order in #AV >>> IS NOT <<<  specified by ISO! ... and is different
in every APL I ever used or wrote.  APL2 allows more than 256 characters -
good for them, someday we'll have user-defined characters, so that everybody
(not just the lucky langauge designers) can create wierd squiggles.

> 4. Is there any standard for the layout of APL characters on a keyboard?

  Indirectly yes.  There is a standard for replacing ASCII keycaps by APL
  keycaps, and there are some loosely followed standards for arranging
  ASCII keycaps on a keyboard.  There are a few recommendations for arranging
  a large set of the overstruck APL chracters on IBM PC keyboards, they
  come from IPSA and STSC, but have not so far as I know been voted on by
  X3J10.

> 5. Is there any standard for an ASCII transliteration of APL
> characters?  Does Dictionary APL have anything to do with this?

There is no standard, there are many systems.  No scheme satisfies all of 
a user's needs.  The ones of the form <escape char> <mnemonic> are the most
common, but the <escape char> is annoying and with a good choice for the
<mnemonic>s, would usually be unnecessary (choose rarely used identifiers
and then require the <escape char> when typing those identifiers, but not
when typing the <mnemonic>).

The <mnemonic>s are best expressed in some natural language, which 
makes ISO standardization very difficult.

> ... a math class that used APL as the main notation?

Many APLers take their notes down in APL, then snooze awhile until the
prof finishes writing out the next monster SIGMA i=1 to n a sub i,j ...
The exercise of translating checks your understanding, but if you misread
your prof, you don't have a fall-back.