Re: from C++ to smalltalk...

[followups set to c.l.s.d]

In comp.lang.smalltalk, [hidden email] (Rick Elbers) wrote:

>Considering for instance my difficulty to create a simple textwindow
>in dolphin to which I can log test messages( Ideally I want to create
>my own workspaces at runtime),


  Just on that narrow point, I think you want something
  like the following (in Dolphin 3.06):

  ...


  | logWindow |

  "open our own TranscriptShell for logging.

   NOTE: we don't use the more normal #show to create it
   as we want a brand new window of the default view
   rather the current Transcript singleton"

  logWindow := TranscriptShell showOn: (String new).

  "now log some messages"
  logWindow show: 'This is a message'; cr; flush.
  logWindow show: 'This is another message'; cr; flush.
  logWindow show: '...And finally a third message'; cr; flush.

  ...

  You'll next probably want to use a customised view
  resource rather than the default one for a TranscriptShell.
  For example you probably want to change the titlebar
  caption to something other than 'System Transcript',
  and then perhaps get rid of the toolbar and edit
  the menus to drop the items that only really make
  sense for the Dolphin IDE.

  To do that open up the Resource Browser, scroll down
  to where in the left hand column (labelled 'Owning
  class') says 'TranscriptShell' and choose 'New>View'
  from the right click menu.  Make your edits and then
  do 'File>Save As' naming the new view 'Log Window'.
  It should appear as a new entry in the Resource
  Browser underneath the old one.

  The updated code to use it would then look something
  like the following:

  ...

  | logWindow |

  "open our own TranscriptShell for logging.  We're
   using a custom view resource that we've saved as
  'Log Window'.  We can use #show: here because
   we're now not using the default view resource"

  logWindow := TranscriptShell show: 'Log Window'.

  "now log some messages"
  logWindow show: 'This is a message'; cr; flush.
  logWindow show: 'This is another message'; cr; flush.
  logWindow show: '...And finally a third message'; cr; flush.

  ...

  HTH!


-- Kapusniak, Stefan e

In article <[hidden email]> on Tue, 28 Nov 2000 16:38:26
+0000, [hidden email] said:

|||   Just on that narrow point, I think you want something
|||   like the following (in Dolphin 3.06):
|||
|||   | logWindow |
|||
|||   "open our own TranscriptShell for logging.

        Thanks for the info. That is something I'd been wanting to do for
quite some time, and this solution never occurred to me. I even went so
far as to add TranscriptShell class>>logWindow to open one of these Log
Windows  more easily. ST is cool...

Joey
--
-- Sun Certified Java2 Programmer
-- Political Rants: www.joeygibson.com
-- My Pocket Smalltalk Stuff: st.joeygibson.com
--
-- "Do you know what I am doing, Miss Kenton? I am placing my
--  mind elsewhere while you chatter away."



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On Tue, 28 Nov 2000 16:38:26 +0000, [hidden email] (Stefan
Elisa Kapusniak) wrote:

Stefan,

I already found the Transcript shell, but show seems overdetermined..?
Show for me is associated with showing a window. And sometimes it
seems so for the transcript, but at othertimes the show is about a
string.

Also I would like to know what the new string has to do with the
transcript in the first example ... And the last point being obvious:
the documentation is incomplete.

For a huge development process that would cost probably at least as
much time as the development-compilation circle. Its a good thing the
MS documents all member functions with examples..

But a lot of thanx for showing this transcript to me...!

Rick

Ric

You wrote in message news:[hidden email]...
> ...
> I already found the Transcript shell, but show seems overdetermined..?
> Show for me is associated with showing a window. And sometimes it
> seems so for the transcript, but at othertimes the show is about a
> string.

Transcript show: 'blah blah', is actually an original Smalltalk-80
incantation which we have had the temerity to deprecate in 4.0. We've never
liked it, and never use it. The standard Smalltalk stream protocols should
be used to print to the Transcript, e.g. #print: (printString of object),
#display: (displayString of object), #nextPutAll: (output a string), etc.
Apart from aesthetic considerations this has the additional benefit that one
can then redirect transcript output to a FileStream (or other stream) by
substitution.

Regards

Blair

On Wed, 29 Nov 2000 10:28:04 -0000, "Blair McGlashan"
<[hidden email]> wrote:

Sounds understandable. And exactly the same as streams in cpp.
Problem in cpp is that sometimes you want the object streamed binary
and sometimes as asci. And streams dont publish if they are either one
of them, so in the end a lot of people dump implementing ostream&
operator << ( const ostream& , const object& )

Another thing. How would you write out the your object to a new
transscript window exactly with the use of display ?

Rick

>
>Regards
>
>Blair
>
>

On Tue, 28 Nov 2000 16:38:26 +0000, [hidden email] (Stefan
Elisa Kapusniak) wrote:

Problem is that I want a new transcript object, not a new class.
I want to use the object methods, which is impossible this way.

Also I have a very hard time setting breakpoints.
Do smalltalkers use those ?

Rick


>
>  HTH!
>
>
>-- Kapusniak, Stefan e

> Also I have a very hard time setting breakpoints.
> Do smalltalkers use those ?

I only figured out how to do this recently myself. Place 'self halt' in
the code.

--
Kevin Powe.

Rick

"Rick Elbers" <[hidden email]> wrote in message
news:[hidden email]...
That's what you'll get. In Smalltalk you can define your own instance
creation methods, and #show: just happens to be one understood by
TranscriptShell; it returns a new TranscriptShell opened on the named view
"resource" (the nearest analaogy in VC to that being a dialog template,
although they are not quite the same things as a view resource is a frozen
live instance, as opposed to a template specification).

> I want to use the object methods, which is impossible this way.

I don't want to confuse the issue, since in this case the logWindow variable
does hold an instance, but one of the significant differences between
Smalltalk and C++/Java, is that classes are first class objects in
Smalltalk. In C++ one has static members that can be scoped to a class, but
this is really only a namespacing of global functions, since the static
members cannot be "virtual". Furthermore static class variables are really
just limited access globals, and are shared by subclasses (i.e. they are not
like instance variables). In Smalltalk a class object has the same
capabilities as any other, and can have instance variables, and polymorphic
behaviour, i.e. you can use treat the thing as an "object" whether you have
a class or an instance. This is extremely useful.

> Also I have a very hard time setting breakpoints.
> Do smalltalkers use those ?

Yes, but much less. In Smalltalk one is immersed in a world of live objects
(the image) which can be interacted with at a fine level of detail. It is
possible to debug individual message sends to individual objects, inspect
them, and generally manipulate them in a much deeper way than one can do in
a static language's debugger. If one wishes to debug an individual method,
one doesn't normally need to set a breakpoint in it, one justs creates the
object with a few expressions, and then evaluates an expression under the
debugger which immediately takes one into the method in which one is
interested. In D3 and D4 this is done using the "Debug-It" command (select
the expression and press F11), and this can be done from almost anywhere,
including in another debugger. A lot of Smalltalk programmers also do a
great deal of programming in the debugger. Changes can be made and the
debugger automatically restarts the method with the new code (this is a bit
like VC's rather good "Edit and Continue", capability, except that it works
99% of the time, rather than 40% of the time, and it is instantaneous).

This is not to say that the sort of powerful breakpoints one finds in
typical C++ IDEs these days would not be useful, just that the need is so
much reduced that implementing them is a lower priority than adding other
features. I know of one Smalltalk that has a more powerful breakpoint
capability, VisualAge, and I think one can purchase an add-on package for
VisualWorks, as well as there being some public domain code in the UIUC
archive. An important point about this is that it is possible for third
parties to add major functionality to the IDE because the language's
environment is all implemented in itself, we aren't talking about just a bit
of scripting or a few macros. If one does't have "proper" breakpoints, then
one inserts 'self halt' statements, conditionally guarded if necessary, in
the code. This is a bit like putting a DebugBreak() in, except of course
that there is no compile-link cycle and hence it doesn't interrupt one's
flow.

All this is pretty meaningless until one has experienced sufficient
Smalltalk programming to "get it". It involves quite a different process and
way of thinking, and this change in the way one works can be quite uncomfort
able (like any change). If one looks for all the things one is familiar with
in C++ and uses that as a measure of Smalltalk, then one is likely to be
disappointed. When I first used it I thought it was bollocks, and it took me
about two weeks of intensive use to convince myself that it was in fact "The
Bollocks". It is also more fun than any other programming language and
environment I have ever used.

Regards

Blair

In comp.lang.smalltalk.dolphin, [hidden email] (Rick Elbers) wrote:

>Another thing. How would you write out the your object to a new
>transscript window exactly with the use of display ?

   Assuming you want to use the default Transcript view
   resource, something like:

     (TransciptShell showOn: (String new)) display: yourObject;
         flush.

   ...Or with a custom view and retaining the the transcript
   in a local variable for further use:

     | logWindow |

     logWindow := TranscriptShell show: 'CustomViewName'.
     logWindow display: yourObject; flush;


   ...on the other hand depending on what you're trying to
   do you might find the following more useful:

      yourObject inspect.


   Which is the code equivalent of selecting an expression that
   evaluates to yourObject and then choosing 'inspect it' from
   the right click menu or hiting Ctrl-I.

   Hope that helps.


-- Kapusniak, Stefan e

In comp.lang.smalltalk.dolphin,
[hidden email] (Stefan Elisa Kapusniak) wrote:

>     | logWindow |
>
>     logWindow := TranscriptShell show: 'CustomViewName'.
>     logWindow display: yourObject; flush;
                                         ^^^
                     
   GAAAAAAAAAAAAHH!!!

   That last semi-colon should have been a period.  Sorry,
   too much coding in Delphi this week...

   ...this month...this year.


-- Kapusniak, Stefan e