atomic toolkit, was Re: [Adobe-source-devel] xstring questions

[Ralph T. <ra...@gm...>]

Having "ordered unnamed dictionary entries" for virtual_machine
functions is good, and really good in the case of an xstring_subst
function (and you're right, even just using a dictionary is far better
than what I was proposing as it syntactically suggests that unique
substitution keys are required [as well as being far prettier]).

One distant future thing that I've been thinking about for a while is
abstracting out some of the policy that client_assembler bakes into
widgets, for example we currently have things like:

panel( bind: @named_value, value: "show_panel" ) { ... }

meaning that the panel is displayed when @named_value is "show_panel";
but what if I wanted to show the panel whenever @named_value !=3D
"show_panel"? I could put a rule into the sheet for this, but would
this be better?

panel( visible: @named_value !=3D "show_panel" ) { ... }

or even to remove visibility from the panel totally:

visible( predicate: @named_value !=3D "show_panel" ) {
  panel() { ... }
}

If you took this idea to it's logical extent (breaking everything down
into atoms) could you define all/most of the widgets in terms of these
atoms? All of the button-type things would be easy, a checkbox might
be:

define_widget( "checkbox", parameters: { name: @cb_name, bind: @cb_value } =
) {
  row() {
    /* how to put "indeterminate" value in here for mousedown (but not
clicked) */
    action( activate: @cb_value =3D !@cb_value ) {
      overlay() {
        visible( predicate: @cb_value =3D=3D true ) { image( src: "checked"=
 ); }
        visible( predicate: @cb_value =3D=3D false ) { image( src: "uncheck=
ed" ); }
      }
      static_text( name: @cb_name );
    }
  }
}

(and then you can use "checkbox" as you currently do, but it's
actually just parameterizing the above definition each time --
@cb_name and @cb_value get replaced; so checkbox( name: "foo", bind:
@my_cell ) means that @cb_name is replaced by "foo" and @cb_value is
replaced by @my_cell).

If it were possible to implement all of the widgets in ui-core in
terms of a small set of atoms (and have a "ui-core prelude file" that
defines all of the ui-core widgets, like checkbox above) then
implementing new widgets (such as those proposed in the wiki) should
mostly be a matter of combining existant atoms (and hopefully atom
implementation is easy enough that adding a new one is still less work
than writing a widget for N platforms).

This "atomic toolkit" idea is clearly only 1/3 baked, I might try to
write a simple implementation of this in Mission to learn more about
the problems involved.

Ralph

On 2/11/06, Sean Parent <sp...@ad...> wrote:
> Foster is the xstring export so I'll let him answer - I suspect we're
> missing an API (I'd rather not have to go through a context for
> replacement) - but I think you should be able to simply create a
> local context as a workaround. I believe you also want to be using
> the marker mechanism for the replacement (Foster?).
>
> For the xstring_sub function call - I don't think you are getting any
> benefit by referring to cells by a quoted name then looking it up
> manually - you can simply use the cell as a variable name. I'd
> recommend making it a function taking named parameters -
>
> xstring_replace(string: "<xstr id=3D'string'><marker id=3D'text'/> the
> number is <marker id=3D'num'/></xstr>",
>                 text: val1, num: val2)
>
> I spent some time looking at some Lua code this last week - I'm
> considering unifying the function mechanism to take a
> pair<dictionary_t, array_t> similar to a Lua table - This would let
> you write:
>
> xstring_replace("<xstr id=3D'string'><marker id=3D'text'/> the number is
> <marker id=3D'num'/></xstr>",
>                 text: val1, num: val2)
>
> And would allow for a single API to plug-in functions. Thoughts?
>
> Sean
>
> On Feb 11, 2006, at 12:15 AM, Ralph Thomas wrote:
>
> > Hi ASL,
> >
> >   I'm trying to write a function to do xstring substitution, which
> > should work something like this:
> >
> > sheet {
> >  interface:
> >   val1 : "hello world, " ;
> >   val2: 17 ;
> >  output:
> >   string <=3D=3D xstring_sub( "<xstring id=3D'text'/> the number is <xs=
tring
> > id=3D'num'/>", [{ name: "text", value: @val1 }, { name: "num", value:
> > @val2 }] );
> > };
> >
> > and have @string be "hello world, the number is 17". I can easily get
> > the values that I need from the sheet, but how can I create an
> > xstring_context_t that contains these values? Is there a way to put a
> > value_t straight in there?
> >
> >
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