Re: Directed vs Generic Syntax

Alex,

You are making good points in favor of the "<p:xslt>" syntax, even if
I still favor the "<p:step>" syntax. But maybe this is too early to
talk about syntax and I suggest we postpone this discussion until we
have made more progress on other issues.

Alex

On 4/20/06, Alex Milowski <alex@milowski.org> wrote:
>
> Alessandro Vernet wrote:
> > On 4/13/06, Norman Walsh <Norman.Walsh@sun.com> wrote:
> >
> > I have to agree with Norm on the question of syntax being discussed here:
> >
> > 1) The schema for the language would depend on the components provided
> > by a given implementation. This is the case with in Ant, but is
> > otherwise fairly unconventional.
>
> It is an extension to the schema.  If we write our schema properly,
> that's OK.
>
> > 2) Extending the pipeline language becomes harder. Say we want in the
> > future the pipeline author to be able to specify that a given input or
> > output has to be valid according to a schema. We would be unable to
> > just add an attribute "schema" on <p:input> or <p:output>.
>
> No harder than adding an extension element in XSLT.
>
> I'm imaging a two part solution to "custom" steps:
>
>    1. A generic "run the step called X" step.
>
>    2. A directed syntax where an step can have its own XML structure
>       to simplify its use.  This is much like how tasks get defined
>       in Ant.
>
> > 3) The syntax imposes unnecessary restrictions: inputs and outputs
> > must have different names, an input cannot be named "input" and an
> > output cannot be named "output".
>
> That's up to the extension to figure out and tell the compiler.
>
> > 4) It becomes impossible to know without knowing the interface of the
> > component being used if a attribute corresponds to an input or an
> > output.
>
> I don't see this as impossible. Components still have to declare their
> signatures for the compiler to know things like you gave it two inputs
> and it only takes one and so that's an error.
>
> --Alex Milowski
>
>


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Received on Wednesday, 26 April 2006 19:01:35 UTC