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Re: Comments on EARL 1.0 LC WD

From: Shadi Abou-Zahra <shadi@w3.org>
Date: Sat, 28 Apr 2007 12:19:14 +0200
Message-ID: <46331FA2.4000605@w3.org>
To: Dominique Hazael-Massieux <dom@w3.org>
CC: public-wai-ert@w3.org

Hi Dom,

Thank you for providing these comments, they have been recorded here:
  - <http://www.w3.org/WAI/ER/EARL10/issues>

Please let us know if you have further input, we will be processing
these comments in the coming weeks.


Dominique Hazael-Massieux wrote:
> Hello,
> Here are a few comments on the Last Call Working Draft of "Evaluation
> and Report Language (EARL) 1.0 Schema", published on March 23 2007 as a
> Last Call Working Draft [1]:
> RDF vs XML
> ----------
> EARL is an RDF vocabulary which I think is a good thing, but is often
> described as an XML one (e.g. the way the contraints are set on
> elements/properties; see also the comment on RFC keywords below).
> I think there ought to be two separate formal specifications (not
> necessarily in separate documents, though):
> * one to express constraints that are true in a RDF world (in term of
> OWL constraints and semantics)
> * one to express constraints on a subset of EARL, that would be enforced
> at the XML level (e.g. through an XML schema, or any other schema
> language), and that would basically define the set of data a given class
> os product (typically, testing software) should be expected to output,
> within a certain well-defined set of XML constraints - this would
> certainly mean reducing the flexibility of the syntax that EARL-as-RDF
> can be expressed through
> The advantage of having both is to have on one hand a formal
> semantically-rich definition of what EARL describes, and on the other
> hand an RDF-compatible XML version of the data that is more likely to be
> parseable through a greater number of tools, with additional semantic
> restrictions (e.g. that all the required data be available in a single
> XML document vs the "open world" hypothesis behind RDF/OWL).
> Use of RFC 2119 Keywords
> ------------------------
> The document uses the RFC keywords to put constraints on the language
> constructions, e.g.:
>         "An Assertion must have exactly one instance of each of the
>         following properties"
> As discussed in the QA Wiki [2], these keywords should preferably be
> used for constraining implementations rather than the language itself;
> this is all the more true given how the constraints are expressed
> semantically: essentially, the OWL ontology says:
> "an Assertion has exactly one instance of each of the following
> properties" (i.e. it is not that it "must" have exactly one, but that if
> more than one is known, that means the two have the same objects, and if
> none is known, it just means that it is yet to be known)
> Thus, I would recommend switching to the declarative form for the
> statements of this sort ("must have" => "has").
> Compound Assertor
> -----------------
> It would be useful to clarify whether either of the following is true:
>         if a given test is determined to pass by a compound assertor,
>         then each of the sub entities of the compound assertor asserts
>         that the test passes
>         vs
>         binding the determination of whether a given test passes to a
>         compound assertor only asserts that the entities taken as a
>         whole asserts that the test passes
> Test Modes
> ----------
> The names used in the classification of the test modes seem a bit weird:
> * "manual" is used to refer to something "based on a person's judgment";
> this reads as "subjective" to me, rather than manual; I don't know if
> the term or the definition is wrong; also, this refers to "a person",
> but does that include organizations as well? (if so, it should probably
> refer to an agent instead; if not, it should be made explicit)
> * "heuristic" reads to me as something that was not 100% surely
> determined, which is quite different from what the current definition
> reads; again, I'm not sure which of the term or the definition is wrong
> * "notAvailable" is not a great name for what is meant either; I would
> think "undetermined" (or maybe "undeterminedMode" for sake of clarity)
> would be closer to what is meant
> Outcome Value
> -------------
> * While I think the 5 defined classes are flexible enough for most
> conformance testing, I'm not sure there is any reason to restrict
> earl:outcome to these 5 classes is necessary; it prevents to re-use EARL
> in other contexts (e.g. performance testing), for no good reason that I
> can see (except over-constraining the RDF for XML-reasons, see comment
> RDF vs XML)
> * "pre-defined values" should read "pre-defined classes"
> Range mixing Literals and Resources
> -----------------------------------
> earl:sourceCopy can take both Literals and URI-s identified resources as
> objects; that seems wrong to me, but I couldn't find anything
> discouraging it explicitly; you may want to ask an RDF-modeling expert
> to check if it's ok, though.
> earl:Content
> ------------
> * How does earl:Content relates to the notion of "Information Resources"
> as defined by the TAG?
> http://www.w3.org/TR/2004/REC-webarch-20041215/#def-information-resource
> It would be useful to clarify whether Content is a subset of
> InformationResource, or the same thing (and if so, it would probably be
> better to re-use an existing vocabulary that describes it).
> * earl:Content mentions only HTTP resources; that excludes HTTPS, but
> also FTP, etc; it may be more appropriate to have a generic earl:Content
> class that doesn't restrict the specific access protocol, and have a
> subclass earl:HTTPContent that allows to identify the well-known case of
> content accessed through HTTP
> RDF Schema
> ----------
> * the rfds:comment for Assertion reads "Parent node that contains all
> parts of an assertion"; this is a syntactic-description (and an
> XML-centered one too) instead of a semantic one that would be expected
> in an RDF schema
> * the description of assertor and single assertor mentions "person" but
> not organizations
> * earl:Content only mentions "on the Web", while the textual definition
> mentions availability through HTTP
> Editorial bugs
> --------------
> * the copyright reads "2007" while the spec was started much earlier
> than that
> * The table of content has two "2.2.1" (the second one should obviously
> be "2.2.2")
> * http://www.w3.org/TR/2007/WD-EARL10-Schema-20070323/#compoundassertor
> reads "these instances can be a Person, Agent, Software, or recursively
> another Compound Assertor"; I think it should either read "a Person,
> Organization, Software, or...", or "an Agent, Software, or ..." (i.e.
> it's not clear why organization doesn't appear while person does)
> HTH,
> Dom
> 1. http://www.w3.org/TR/2007/WD-EARL10-Schema-20070323/
> 2. http://esw.w3.org/topic/RfcKeywords

Shadi Abou-Zahra     Web Accessibility Specialist for Europe |
Chair & Staff Contact for the Evaluation and Repair Tools WG |
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Received on Sunday, 29 April 2007 08:29:36 UTC

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