Hi,
On 18/05/10 11:02 PM, "Kamm Christian.D (Nokia-D/Berlin)"
<christian.d.k...@nokia.com> wrote:
> I think it'd be good to have an annotated grammar of the Qml language in the
> documentation. The current way of teaching by example is great for new users.
> It isn't very good as a quick reference, a reliable way to resolve corner
> cases or to figure out whether something is valid Qml.
Great! I've started on this a number of times, but never really got
anywhere before being distracted. Perhaps someone with more discipline will
have more luck.
> QmlProgram:
> QmlImport* QmlObjectDefinition
>
> QmlImport:
> 'import' QmlImportId QmlImportVersion ('as' QmlIdentifier)?
> 'import' StringLiteral QmlImportVersion? ('as' QmlIdentifier)?
>
> QmlImportId:
> IdentifierName ('.' IdentifierName)*
>
> The implemented grammar just says "QmlImportId: MemberExpression" and has an
> extra check to verify it's either a string literal or a series of
> FieldMemberExpressions in the parsing code. I think this should be explicit in
> the documentation. It may also be worthwhile to change the grammar like this
> to allow using reserved words for qualified imports.
Agreed.
> QmlImportVersion:
> DecimalIntegerLiteral '.' DecimalDigits
>
> The implemented grammar uses NumericLiteral here. Being more explicit shows
> that 1.5e9 is not a valid import version more clearly.
Sure, if you're happy to type "import Qt 4.1500000000" in another 1499999993
releases of Qt :) Ok, DecimalDigits makes more sense.
> QmlObjectMember:
> QmlPropertyDeclaration
> QmlPropertyBinding
> QmlObjectDefinition
> QmlSignalDeclaration
> FunctionDeclaration
>
> Omitted VarDeclaration.
Do you mean the "UiObjectMember: VariableStatement" clause? I think that
should be removed. Roberto?
> QmlPropertyDeclaration:
> 'property' QmlPropertyType QmlIdentifier (':' QmlPropertyRhs)?
> 'property' 'list' '<' QmlQualifiedId '>' (':' '[' QmlArrayMemberList?
> ']')?
> 'default' 'property' 'alias' QmlIdentifier ':' QmlPropertyRhs
>
> This is different from the implemented grammar in several ways.
>
> 1. It allows any right-hand side that's valid in a property binding as the
> initializer of a declaration. While separating the two may make sense to
> programmers, what's the harm in making
>
> property int foo : 3*width
>
> be equivalent to the following:
>
> property int foo
> foo: 3*width
It *should* be the same. I thought this had been fixed, but I guess not :(
> 2. I changed the list type from list<QmlIdentifier> to list<QmlQualifiedId> to
> allow lists of types that have been imported into a namespace. This seems to
> be an oversight in the current implementation.
Yep
> 3. is there any use for 'default' properties that don't have 'alias' type? I
> couldn't think of any and altered the grammar accordingly.
Object and list properties can be default. "default property Object blah"
for example.
> QmlPropertyType:
> QmlIdentifier
>
> I dropped ReservedWord and 'var'. The latter is deprecated and no Qml types
> seem to be reserved words.
Ok.
> I'll open tickets for these bugs/suggestions in a few days, depending on the
> feedback.
Please do.
Cheers,
Aaron
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