[Seaside-dev] Re: Seaside2.8a1-mb.487

[Philippe Marschall]

2007/10/1, Bany, Michel <mbany at cincom.com>:
> > > I do not see #displayString as a conversion method but rather as a
> > > method that produces string representations of objects for the user
> > > interface, somehow similar to #printString. Also, using
> > #displayString
> > > is a little more than a convention. VW does not and cannot have
> > > #asString implemented in Object, therefore using  something
> > else than
> > > #asString for getting string representations of objects was an
> > > obligation in order to make Seaside portable, rather than a
> > > convention. See below the (nearly) complete story as to why Seaside
> > > uses #displayString.
> >
> > So basically neither #displayString nor #asString will ever work.
> > Which just means we will have to introduce our own method for
> > string conversion that is used by no other Smalltalk (or wait
> > for ANSI, *jk*). This doesn't really take me by surprise to
> > so I have a concrete
> > proposal: #toString. Yes, it's Java-esque but this is good
> > thing since it means that we have no conflicts with existing dialects.
>
> Again, #displayString is not intended as a string conversion method,
> but as a method for displaying an object to the user interface. When
> you need a string conversion method use #asString. When you need a
> displayable string for an object use #displayString. Most of the time
> the result will be the same, but the intentions are different.

Wow, that is a huge change to the current system. Today we use
#displayString as a conversion method because we have been told again
and again that we can not use #asString as a reliable string
conversion method on VW. To make matters worse in some cases (again on
VW) #displayString does actually not return a String but a Text. There
is a very fine distinction between 'for conversion' and 'for display'.
Going through the roughly hundred senders of #displayString we have
for many of them I can't say which one it should be. Wasn't Smalltalk
about making simple things simple?

> So why no just accept the change I suggested to #asFilename: where
> we do not want to display anything to the user interface and where
> we clearly need to convert a selector Symbol to a String.

Because it is extremely inconsitent. We use #displayString everywhere
but there as a conversion method.

Cheers
Philippe

> asFilename: aSelector
>         | dotIndex extension |
>         dotIndex := self lastUpperCaseIndexIn: aSelector.
>         dotIndex = 0
>                 ifTrue: [^ aSelector asString].
>         extension := (aSelector last: aSelector size - dotIndex + 1)
> asLowercase.
>         ^ (aSelector first: dotIndex - 1)
>                 , '.' , extension
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