Hi!

At the end of this message I added rot13 written in Tao. If you do not
know it: rot13 is a Cesar encoding; an implementation of rot13 using
standard Unix tools is

tr '[a-zA-Z]' '[n-za-mN-ZA-M]'

The Tao script works flawlessly - for a single line. I am an old Linux
hand so I have two questions not answered by the documentation.

 - How to make the program iterate over all input provided via
   standard input unless EOF is encountered?

 - How to access command line arguments?

The reason is obvious: Without these two means it is impossible to
write Unix style tools in Tao that are capable of both processing
input streams and files. Bad.

I am pretty sure most people who know why this is bad but perhaps not
all do. I therefore describe my motivation for having such
capabilities.

A typical problem when dealing with data is this:

You have to implement operation F on data of the same type that is
provided by different sources and need to be provided to other people.
While the data are in principle always of the same type you have to
deal with input formats i1, i2, i3, ..., iN and output formats o1, o2,
o3, ... oM. If you implement all functionality in one program you end
up with always modifying the program whenever a new source is added.
Bad. A data processing program should only be modified if the
information it processes, the information it extracts or the way in
which the information input is transformed into the information output
(i.e. the algorithm) changes but it should *never* need to be modified
if the representation of the data is changed without actually
modifying the informational content. It's simply the "never change a
winning team" (aka "never touch a running system") issue. It is much
better to have filters that transform i1, i2, i3, ..., iN into a
generic input format I, then process this input with a program that
produces some generic output format O and have this output then
transformed by other filters into any of o1, o2, o3, ..., oM.

A great example of tools that follow this style is netpbm that comes
with filters that transform an awful lot of graphics formats into a
PBM (a trivial graphics format) and others that transform PBM into an
awful lot of output formats (there are also programs that can do
quantization and the like so F is known to exist as well :-). If
netpbm does not support your format simply write two tools: One that
transforms the format to PBM and one for the opposite direction. Now
netpbm supports your format.

Enough motivation, here's code (note that it does not work on EBCDIC
systems!):

a    = read();
orig = unpack(a);
rot  = { };
foreach(orig:x) {
  if (x >= unpack("a")[0] && x <= unpack("z")[0]) {
    x = (x + 13 - unpack("a")[0]) % 26 + unpack("a")[0];
  } else if (x >= unpack("A")[0] && x <= unpack("Z")[0]) {
    x = (x + 13 - unpack("A")[0]) % 26 + unpack("A")[0];
  }
  rot.insert(x);

print (pack(rot), "\n");

Before I forget to ask: Does "rot[rot.#] = x" fail on purpose instead
of meaning the same as "rot.insert(x)"?

Josef 'Jupp' SCHUGT
--
"NO" to the European constitution means "YES" to democracy, not "NO" to
Europe - presently Europe as a whole is governed by a central committee
while the parliament only has very limited power. Thank you, France.

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This is a re-sended message which was not previously sent to this mailing
list by mistake :)

Hi!

The feature in your first question is not implemented, I will do it.

The command line arguments are stored in an array named COMARG, which has to
be accessed by the current namespace"this", namely, this.COMARG or
this::COMARG.

This command argument accessing was not elegantly support, probably it will
be changed. And probably in the following ways, "this" will be given the
same meaning as in C++ to mean the current object, the current namespace
will be accessed with "here"; A special namespace will be used to store
command line arguments, environment variables etc... For convenience,
accessing classes and routines in a namespace will not require expilicit
specifying its namespace, they will be searched automatically from current
namespace and other namespace accessable from the current namespace.

"rot[rot.#] = x" fails on purpose ( I should have let it give a warning),
since "rot" is an array. If "rot" and "x" are strings, "rot[rot.#] = x" will
insert "x" to the end of "rot". This kind of operation is not supported for
array because if "x" is also an array, "rot[rot.#] = x" will be ambiguous,
since "x" can be inserted into "rot" as a whole or element by element.

I understand your motivation for having such capabilities. Your suggestions
are very good, by myself alone I can't have prevision for all possible
important features for the language. Thank you for the suggestions :-)

Limin FU

On 6/1/05, Josef 'Jupp' SCHUGT <j...@gmx.de> wrote:

Hi!

At Mon, 6 Jun 2005 11:08:35 +0200, Limin Fu wrote:

What mail user agent (aka mail client) do you use? I use wanderlust
and rather happen to send answers to too many recipents - Per default
it addresses answers both to the author of a message and to the list
the messages was delivered to - which only makes limited sense because
the author of a message usually is subscribed to that list and
therefore receives the message twice. That is one of the few things
mutt is better at :-)

BTW: You should consider not to use TOFU - (your) *t*ext *o*n-top,
*f*ull-quote *u*nderneath (it)[1]. There are several reasons why one
should not use it. The most important (at least to me) is that
switching back and forth between the answer and the original message
takes more time and is more confusing than reading the question that
is immediately followed by the answer.

The best way of finding lacking features of a programming language is
writing programs in it. If one finds out that something cannot be done
one has to decide if one wants to implement the feature(s) require for
that task or to refrain from supporting it. Recursion is such a
feature: FORTRAN 77 does not support it - by intention. Such design
decisions should not to be fixed for eternity but should be overhauled
now and then. Guess what? Fortran 90 *does* support recursion.

[1] The correct etymology of the acronym is German "Text oben
Fullquote unten" (I tried my best to provided an appropriate
translation that results in the same acronym).

All for now,

Josef 'Jupp' SCHUGT
--
Your computer seems to have been infected by "nTOSkrnl.exe" (the "New
Tramiel Operating System" is a revised version of the Atari ST/TT
operating system and is known not to run on a PC). Please make sure to
remove any file with that name…

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Hi!

What mail user agent (aka mail client) do you use? I use wanderlust

Usually I use the web browser to check and send email in my gmail acount, I
find it is enough convenient, because it can group emails according to
topics, like a forum does. Another reason is, when I register this gmail
account, it didn't support POP client, though now it does.

Last time I replied your post in the list by clicking "reply" instead of
"reply all", so it just sent it to you. This time I clicked "reply all", and
you will receive it twice :)

BTW: You should consider not to use TOFU - (your) *t*ext *o*n-top,

Yes, sometime I also reply in this way of breaking the original message and
inserting answers, especially when there are too many questions to answer.
It's really more convinient to discuss something by email in this way.

The best way of finding lacking features of a programming language is

You are right, that's what I'm doing. I started to use Tao language in my
work since March, since then, Tao really improved a lot.

Recursion is such a

I think there were something similar in Tao, which I thought were not really
necessary, but in the end, when I started to writing program in Tao, I found
it was important to have them in Tao :-)

[1] The correct etymology of the acronym is German "Text oben

You did it!
Limin