Hi,
Yes, the syntax are very similar but not identical.
There is a minor difference: I do not make use of the <appinfo> wrapper.
XSD syntax:
<annotation>
<documentation> anything goes </documentation>*
<appinfo source="URI"?> xsd:any </appinfo>*
</annotation>
BPEL syntax:
<annotation>
<documentation> anything goes </documentation>*
xsd:any*
</annotation>
If people have strong opinion of having similar to <appinfo>, I don't
mind adding it.
As of now, I don't see a big need of it.
Regards,
Alex Yiu
Assaf Arkin wrote:
> If I remember correctly, the XSD syntax is:
>
> <annotation>
> <documentation> anything goes </documentation>
> <appinfo> anything goes </appinfo>?
> </annotation>
>
> All application extensions are placed in the appinfo element of the
> annotation element.
>
> Assaf
>
> Alex Yiu wrote:
>
>>
>> Hi, all,
>>
>> I would like to discuss the following issue in upcoming BPEL F2F:
>> either as a standalone issue or as a sub-issue Issue 111 or Issue 11.
>>
>> =============================================
>>
>>
>> Fixing up extensiblity syntax in BPEL by using <annotation>
>> pattern
>>
>>
>> _*Issue Description:*_
>>
>> Currently, we have a number of places which make uses of <xsd:any>
>> (aka extensibility or xml-data placeholder) in our BPEL language:
>>
>> 1. xsd:any to any BPEL activity and bpws:tExtensible construct:
>> e.g. <empty>, <sequence> or <flow>)
>> 2. literal form of from-spec
>> 3. query and expression language as a result of Issue 13
>> 4. extended assign operation as a result of Issue 11.1
>> 5. Other extensibilities: e.g. extension actvity if we pass Issue 111
>>
>>
>> Mix and matching all these extension points and xsd:any produces a
>> bunch of syntax and semantic ambiguities. Given our current extension
>> syntax, we find it very difficult to come-up a very clear and
>> easy-to-use syntax grammar.
>>
>> Since not all the people on this email list are XSD experts here, I
>> am going to illustrate those ambiguities by some samples and EBNF:
>>
>> * _Semantic ambiguity in from-spec:_
>> E.g.:
>> <from>
>> <foo:extensionToFromSpec />
>> <bar:literalFromData />
>> </from>
>>
>> Here we have two elements of other namespace. One is the
>> extension of from-spec. One is the literal data for the
>> from-spec. By just looking into the syntax / parse-tree, without
>> looking into its semantics, we CANNOT tell which elements fits
>> which role!!!
>>
>> Paul Brown from FiveSight reported in a similar problem before:
>> [ See:
>> http://lists.oasis-open.org/archives/wsbpel/200410/msg00077.html
>> - item (3) ]
>>
>> * _Syntax ambiguity in <assign>_
>> E.g.:
>> <assign>
>> <foo:transactionEnabled />
>> <foo:xmlDataOp />
>> <copy>
>> <from>...</from>
>> <to>...</to>
>> </copy>
>> </assign>
>>
>> Informal EBNF for assign
>> assign ::= <assign> <documentation>* *any** <targets>? <sources>?
>> ( *any* | <copy> )+ </assign>
>>
>> As a result of Issue 11.1, under <assign>, we have both an
>> extension to <assign> (i.e. <foo:transactionEnabled />) and an
>> extended xml manipulation operation (i.e. <foo:xmlDataOp />).
>> Again, by just looking into the syntax / parse-tree, we CANNOT
>> tell which elements fits which role (*xsd:any*)!!!
>>
>> [ One additional caveat is: when the above syntax is mixed with
>> source or target control links. Those source and target elements
>> will be inserted between <foo:xmlDataOp> and <copy>. This caveat
>> was discovered by Yaron. ]
>>
>>
>> These ambiguities are definitely undesirable. They are sometimes even
>> illegal or creates misleading syntax. The illegal case is known as:
>> ambiguous grammar problem. As long as we are using context-free
>> grammar (e.g. EBNF) to construct parse tree, it seems to us that we
>> cannot escape this clasical ambiguous grammar problem with our
>> current extension syntax. In the XSD world, this ambigous grammar
>> problem is known as "indeterministic content model", which is illegal
>> in XSD.
>>
>> *_Submitter's Proposal: _*
>>
>> Some of us have banged our heads to the table to try to resolve this
>> problem while keeping the same level of BPEL extensibility. Finally,
>> we think we find the solution: _to apply a syntax pattern similar to
>> <xsd:annotation> to BPEL_.
>>
>> We suggest to have a <annotation> wrapper element to clearly separate
>> the element-based extension to any Extensible BPEL Construct
>> (bpws:tExtensible). After applying <annotation> pattern, the
>> previously ambigous examples would become like the following:
>>
>> <from>
>> *<annotation> *
>> <foo:extensionToFromSpec />
>> *</annotation>*
>> *<literal>*
>> <bar:literalFromData />
>> *</literal>*
>> </from>
>>
>> (We also add <literal> as a separator per Paul Brown's suggestion and
>> that will allow use to use any namespace inside the <literal> element.)
>>
>> <assign>
>> *<annotation>*
>> <foo:transactionEnabled />
>> *</annotation>*
>> <foo:xmlDataOp />
>> <copy>
>> <from>...</from>
>> <to>...</to>
>> </copy>
>> </assign>
>>
>> Now those ambigous extension entries are nicely seperated.
>>
>> Informal EBNF for assign will become:
>> annotation ::= *<annotation>* <documentation>* *any* <annotation> *
>> assign ::= <assign> *<annotation>?* <targets>? <sources>?
>> ( *any* | <copy> )+ </assign>
>>
>>
>> This will solve Issue 111 grammar as well. E.g.:
>>
>> <sequence>
>> *<annotation>*
>> <foo:extensionToSeq />
>> *</annotation>*
>> <foo:barExtendedActivity />
>> <invoke ... />
>> ...
>> </sequence>
>>
>>
>> Please note that this <bpel:annotation> is VERY similarly to
>> <xsd:annotation> design pattern. Existing XSD users should have no
>> problem in learning this pattern.
>>
>>
>>
>> _*Details XSD Changes:*_
>>
>> -----------------------------
>> * <element name="annotation">
>> <complexType>
>> <sequence>
>> <element ref="bpws:documentation" minOccurs="0"
>> maxOccurs="unbounded" />
>> <any namespace="##other" processContents="lax"
>> minOccurs="0" maxOccurs="unbounded"/>
>> </sequence>
>> </complexType>
>> </element>*
>> <complexType name="tExtensibleElements">
>> <annotation>
>> <documentation>
>> This type is extended by other component types
>> to allow elements and attributes from
>> other namespaces to be added.
>> </documentation>
>> </annotation>
>> <sequence>
>> *<element ref="bpws:annotation" minOccurs="0"/>*
>> </sequence>
>> <anyAttribute namespace="##other" processContents="lax"/>
>> </complexType>
>> -----------------------------
>>
>> -----------------------------
>> <group name="activity">
>> ...
>> <choice>
>> <element name="empty" type="bpws:tEmpty"/>
>> <element name="invoke" type="bpws:tInvoke"/>
>> <element name="receive" type="bpws:tReceive"/>
>> <element name="reply" type="bpws:tReply"/>
>> <element name="assign" type="bpws:tAssign"/>
>> <element name="wait" type="bpws:tWait"/>
>> <element name="throw" type="bpws:tThrow"/>
>> <element name="rethrow" type="bpws:tRethrow"/>
>> <element name="exit" type="bpws:tTerminate"/>
>> <element name="flow" type="bpws:tFlow"/>
>> <element name="switch" type="bpws:tSwitch"/>
>> <element name="while" type="bpws:tWhile"/>
>> <element name="sequence" type="bpws:tSequence"/>
>> <element name="pick" type="bpws:tPick"/>
>> <element name="scope" type="bpws:tScope"/>
>> <element name="compensate" type="bpws:tCompensate"/>
>> * <!-- this xsd:any is for Issue 111, if we pass it -->
>> <any namespace="##other" processContents="lax" />
>> * </choice>
>> </group>
>> -----------------------------
>>
>> -----------------------------
>> <complexType name="tAssign">
>> <complexContent>
>> <extension base="bpws:tActivity">
>> * <!-- for Issue 11.1 -->
>> <choice maxOccurs="unbounded">
>> <element name="copy" type="bpws:tCopy" />
>> <any namespace="##other" processContents="lax" />
>> </choice>
>> * </extension>
>> </complexContent>
>> </complexType>
>>
>> * <element name="literal">
>> <complexType mixed="true">
>> <sequence>
>> <any processContents="lax" minOccurs="0"
>> maxOccurs="unbounded"/>
>> </sequence>
>> </complexType>
>> </element>*
>> -----------------------------
>>
>>
>> -----------------------------
>> *<!-- pre 103 --> *
>> <complexType name="tFrom">
>> <complexContent>
>> <extension base="bpws:tExtensibleElements">
>> <sequence>
>> <choice minOccurs="0">
>> * <any namespace="##other"
>> processContents="lax" />*
>> <element ref="bpws:query"/>
>> <element ref="bpws:expression"/>
>> <element ref="bpws:service-ref"/>
>> *<element ref="bpws:literal" />*
>> </choice>
>> </sequence>
>> <attribute name="variable" type="NCName"/>
>> <attribute name="part" type="NCName"/>
>> <attribute name="property" type="QName"/>
>> <attribute name="partnerLink" type="NCName"/>
>> <attribute name="endpointReference" type="bpws:tRoles"/>
>> <attribute name="opaque" type="bpws:tBoolean"/>
>> </extension>
>> </complexContent>
>> </complexType>
>> <element name="to">
>> <complexType>
>> <complexContent>
>> <restriction base="bpws:tFrom">
>> <sequence>
>> * <element ref="bpws:annotation"
>> minOccurs="0"/> *
>> <choice minOccurs="0">
>> <element ref="bpws:query"/>
>> </choice>
>> </sequence>
>> <attribute name="opaque" type="bpws:tBoolean"
>> use="prohibited"/>
>> <attribute name="endpointReference"
>> type="bpws:tRoles" use="prohibited"/>
>> </restriction>
>> </complexContent>
>> </complexType>
>> </element>
>> -----------------------------
>>
>>
>> ----------------------------- *<!-- post 103 -->*
>> <complexType name="tFrom" mixed="true">
>> <sequence>
>> *<element ref="bpws:annotation" minOccurs="0"/>*
>> <choice minOccurs="0">
>> *<any namespace="##other" processContents="lax" />
>> <element ref="bpws:literal" />
>> * <element ref="bpws:service-ref"/>
>> </choice>
>> </sequence>
>> <attribute name="expressionLanguage" type="anyURI"/>
>> <attribute name="variable" type="NCName"/>
>> <attribute name="property" type="QName"/>
>> <attribute name="partnerLink" type="NCName"/>
>> <attribute name="endpointReference" type="bpws:tRoles"/>
>> <attribute name="opaque" type="bpws:tBoolean"/>
>> <anyAttribute namespace="##other" processContents="lax"/>
>> </complexType>
>>
>> <element name="to">
>> <complexType mixed="true">
>> <sequence>
>> * <element ref="bpws:annotation" minOccurs="0"/>
>> <any namespace="##other" processContents="lax"
>> minOccurs="0" />*
>> </sequence>
>> <attribute name="queryLanguage" type="anyURI"/>
>> <attribute name="variable" type="NCName"/>
>> <attribute name="property" type="QName"/>
>> <attribute name="partnerLink" type="NCName"/>
>> <anyAttribute namespace="##other" processContents="lax"/>
>> </complexType>
>> </element>
>> -----------------------------
>> =============================================
>>
>>
>>
>> Thanks!
>>
>>
>> Regards,
>> Alex Yiu
>>
>>
>>
>
