[Cuis-dev] reflection and questionable tab completion

[Hernán Wilkinson]

Hi Mark,
 Smalltalk is a dynamically typed language, therefore the autocompletion
tries to do its best due to the lack of type info.
 For sure you noticed that some selectors that the autocomplete shows are
in black and some are in blue. The ones in black are the ones that for sure
the receiver of that message will answer, the ones in blue are the ones
that the autocomplete does not know.
 In your example, the selector packages is in blue because Smalltalk is an
object whose type is well known by the environment and it will not answer
that message. (Please do not confuse Smalltalk the language/environment
with Smalltalk the object)
 Just to clarify, Smalltalk is a global var that references an object
instance of SystemDictionary, if you write "Smalltalk " (without the
quotes) and press tab (*), the autocompletion will show you all the
messages that Smalltalk will answer for sure. If you press "p" it will show
you all the selectors that start with p, but if you press "pa" you will see
they are in blue, that means that Smalltalk will not answer those messages.
 Inferring what messages Smalltalk will answer is simple due to what I said
in the previous paragraph, but most of the cases are not like that. For
example, if you have the method "m1: something", what is the type of
"something"? how can we infer the messages it will answer? There are many
techniques, for example type inference (but it is slow and not "complete"),
another is something we implemented in Cuis called "LivedTyping" where
types of variables are collected dynamically and that info is used in all
the tools, specially in the autocompletion.
 The UX with LiveTyping is completely different because it is like having
tools of a statically typed language but in a dynamically typed one. If you
want to try it, download CuisUniversity from
https://sites.google.com/view/cuis-university/descargas?authuser=0 that has
LiveTyping installed. (The site is in Spanish, but you will understand :-)
).

 I hope I answered your question, it is an interesting topic :-) If you
have questions let me know.

Cheers!
Hernan.

(*) For the autocompletion to open when you press tab this preference must
be set:
Preferences name: #spaceTabOpensAutoCompletion category: #gui value: true.



On Fri, Jun 14, 2024 at 2:14 PM Mark Volkmann via Cuis-dev <
cuis-dev at lists.cuis.st> wrote:

> I'm learning about reflection in Smalltalk and trying out a bunch of
> related methods. When I enter Smalltalk and part of a message name in a
> Workspace and press the tab key I get lots of suggested completions. But
> many of them give me MessageNotUnderstood when I "Print it". For example:
>
> Smalltalk packages
>
> Why would it suggest completions that aren't really implemented?
>
> --
> R. Mark Volkmann
> Object Computing, Inc.
> --
> Cuis-dev mailing list
> Cuis-dev at lists.cuis.st
> https://lists.cuis.st/mailman/listinfo/cuis-dev
>


-- 

*Hernán WilkinsonAgile Software Development, Teaching & Coaching*
*Phone: +54-011*-4893-2057
*Twitter: @HernanWilkinson*
*site: http://www.10Pines.com <http://www.10pines.com/>*
Address: Alem 896, Floor 6, Buenos Aires, Argentina
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