To allow writing a schema that describes non-ASCII element/attribute names with an editor that doesn't support them, we might want to have character escapes in the compact syntax, just like Java or XML.

Such escapes are also useful for parameter names and their values.

In the current draft, nc1 '-' nc2 is used to represent the "except" clause. However, to increase the readability, it was suggested that we should use the keyword "except" instead of a dash.

The current draft doesn't have any mechanism to specify the encoding of a RELAX NG grammar writtein in the compact syntax. Therefore, it must be specified as out-of-band information (such as a parameter to the command line.)

To avoid this inconvenience, it was suggested to add something like the XML declaration to the header.

It was suggested that it would be nice if the compact syntax specifies the mapping between comments in the compact syntax and <a:documentation> in the XML syntax. In this way, comments in the compact syntax would be automatically copied into XML syntax as <a:documentation> element.

The compact syntax doesn't have the equivalent of <div> in the XML syntax.

The current syntax doesn't allow namespace<->prefix bindings to be declared locally. This prevents some grammars written in XML from being converted into a compact syntax (see below.)

  
  

]]>

It might be nice if the compact syntax allows users to write a long string literal (such as a complex regular expression) in multiple lines, just like in C.

The syntax currently allows newlines inside strings. Do we want to prohibit them?

Do we allow a schema written in the XML syntax to include or externalRef another schema written in the compact syntax (or vice versa)?

W3C XML Schema Datatypes are practically only one interoperable datatype library. And many people are using it with RELAX NG.

To make a life relaxing for those majority, do we want to pre-declare the prefix "xsd" for "http://www.w3.org/2001/XMLSchema-datatypes"?

John Cowan suggested that the keyword "externalRef" should be changed to "external" just like the keyword of <parentRef/> is "parent".

This leaves "notAllowed" as the only camel notation keyword, which leads to another issue of whether we should also change this keyword to completely get rid of camel notation keywords.

Shall we allow attribute name {} just like we allow <attribute name="name"/>?

Should we make quotes on parameter values optional when the value is an NMTOKEN: xs:string { minLength = 1 }

Currently, we need to write minLength="1"

A feedback from RelaxNGCC claims that it becomes awkward to write lengthy character data inside foreign elements in the compact syntax.

Currently, we need to quote all character data inside elements. Shall we provide another syntax to make this less painful? If so, how?

A feedback from RelaxNGCC also reveals a case where the current annotation syntax doesn't quite work well.

In a nut-shell, the compact syntax has an assumption as to the use of annotation --- it is assumed that an annotation is always attached to the parent element. But RelaxNGCC is using annotations in a different way.

Because of the popularity of XML Schema Datatypes as THE datatype library, it might be worthy to pre-declare the "xsd" prefix for "http://www.w3.org/2001/XMLSchema-datatypes". Users no longer need to type a datatype library declaration if s/he is going to use this library, which is highly likely.

Of course the "xsd" prefix can be overrided manually.

James proposed that () could be used instead of empty. In fact, this is what XQuery does.

John Cowan listed arguments against the annotation syntax.

John Cowan proposed to allow these combinaors right before a right parenthesis so that a list of items can be written beautifuly (and easy to maintain.)

bar = element bar {
  element bar1 {text},
  element bar2 {text},
  element bar3 {text},
}

Murata-san pointed out the lack of type information in the current notation of the formal description of the compact syntax.

In section 6.3, the wording currently reads "For this purpose, two instances of data model ... are considered loosely equivalent if they are identical after applying all the simplification ..."

But they may not be identical, because processors can choose names on <define>s freely and put them in any order.

Paul and David suggested to use "@foo {...}" instead of "attribute foo {...}" and "<foo> {...}" instead of "element foo {...}" to make the compact syntax even more compact.

The following schema produces two document elements, which is not well-formed.

## Oops
"Just a value pattern"

People often use #################### as a formatting aid (for example to separate sections.) According to the current draft, this will be also transformed into a documentation element (except the first two ##).

The current syntax cannot create an annotation element with both attributes and text content.

x:foo [ bar="baz" "some content" ]

Because the above will not work due to literal segment concatenation.

Annotation elements (foreign namespace elements) and RELAX NG DTD compatibility annotation are both refered to by the word "annotation".