[Pharo-project] Transcript rant

Fernando Olivero fernando.olivero at usi.ch
Mon Apr 4 14:46:19 CEST 2011

Transcript could be polymorphic with a Stream, not necessarily a
subclass. Lets identify the methods that are missing and add them. For
instance, existing methods are: Transcript class >> nextPutAll:

Transcript is the model. TranscriptMorph is the view. Currently the
morph just displays a Form showing the model's contents. Wouldn't take
much to alter to present a TextMorph ( read-only right?).

Transcript behavior is in the class side because somehow its mimicking
a singleton, Transcript is still supposed to be unique in the image.
And thread safe, and enabling logging to file also.


On Mon, Apr 4, 2011 at 2:28 PM, Igor Stasenko <siguctua at gmail.com> wrote:
> It is broken, badly broken..
> of course its a piece of cake to add #ensureCr method , so VMMaker
> will work properly..
> but the problem is that Transcript from Cuis is even worse than we had before.
> First thing, is that Transcript is no longer a global variable, but
> instead a singleton class (Transcript).
> So, now, what i suppose to do if i want to redirect all
> Transcript show: ...
> to file instead of in-image stream?
> Second. I told it before and i will repeat it again.
> Transcript ===== WriteStream
> yes, it is stream.
> And Transcript as a tool  - a window which you see on desktop is a
> view of that stream. Do you follow?  Transcript is model, and
> transcript window is view. Simple enough?
> Then why its not like that?
> So, we should have a model,  which is a stream,
> and as many as we like views, which simply listening of updates on
> that stream and updating their view correspondingly..
> This means that to do it right, we should do something like following:
> - Transcript is a stream, but which also notifies the view(s) about
> new stuff coming in, so views can react and update themselves
> - Transcript is write only stream, and any attempts to seek or read
> from it should be prohibited. Sorry guys.. if i'd like to do
> transcript logging via socket,
> where i suppose to take a content which i already sent via wire?
> it would be really nice to have xtreams, which allow stream
> composition.. so then transcript is a composed stream of a following
> form:
> notifier stream -> output stream
> notifier stream is direct any writes to output stream, but in addition
> it notifies any listeners about new content are written to it. This is
> easy to implement using xtreams..
> but not so easy with old streams (but its doable).
> An output stream could be anything, which application/image wants to be.
> For obvious reasons, i'd like to redirect all transcript output in
> headless mode to stdout. It was doable with old implementation.. but
> with a new one its impossible, because then i will need to replace
> class with something else,
> and then restore it back when i have to switch back to normal operation...
> Views.. Views are receiving notifications and update their own
> contents (usually text morphs). There could be as many as one wants
> views on transcript stream. Not only one.
> I really don't like that in new transcript i can't even select a text
> or clear window... from my POV this is what called regression.
> Make it simple, but not simpler (c) Albert Einstein.
> --
> Best regards,
> Igor Stasenko AKA sig.

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