##This syntax support the bare minimum for DSDL Part 7.

## graphemes are not supported
## kenel-and-hull are not supported

## We can further simplify [13] by removing negCharGroup
## and charClassSub, since they are similar to "difference".

default namespace = "toBeSupplied"

coll = union | difference | ref | charGroup
union = element union { coll, coll+ }
difference = element difference { coll, coll }
ref =
    element ref {
        attribute href { xsd:anyURI }
    }
charGroup = element charGroup { text }

##The content of an charGroup element matches charGroup
##as specified by the following rules.
## 
## [12] charClassExpr ::= '[' charGroup ']'
## [13] charGroup ::= posCharGroup | negCharGroup | charClassSub
## [14] posCharGroup ::= ( charRange | charClassEsc )+
## [15] negCharGroup ::= '^' posCharGroup
## [16] charClassSub ::= ( posCharGroup | negCharGroup ) 
##                       '-' charClassExpr
## [17] charRange ::= seRange | XmlCharIncDash
## [18] seRange ::= charOrEsc '-' charOrEsc
## [20] charOrEsc ::= XmlChar | SingleCharEsc
## [21] XmlChar ::= [^\#x2D#x5B#x5D]
## [22] XmlCharIncDash ::= [^\#x5B#x5D]
## [23] charClassEsc ::= ( SingleCharEsc | MultiCharEsc
##                         | catEsc | complEsc )
## [24] SingleCharEsc ::= '\' [nrt\|.?*+(){}#x2D#x5B#x5D#x5E]
## [25] catEsc ::= '\p{' charProp '}'
## [26] complEsc ::= '\P{' charProp '}'
## [27] charProp ::= IsCategory | IsBlock
## [28] IsCategory ::= Letters | Marks | Numbers
##                     | Punctuation | Separators | Symbols | Others
## 
## The semantics of [29] thru [37] depend on the version of the Unicode 
## standard.
## [29] Letters ::= 'L' [ultmo]?
## [30] Marks ::= 'M' [nce]?
## [31] Numbers ::= 'N' [dlo]?
## [32] Punctuation ::= 'P' [cdseifo]?
## [33] Separators ::= 'Z' [slp]?
## [34] Symbols ::= 'S' [mcko]?
## [35] Others ::= 'C' [cfon]?
## [36] IsBlock ::= 'Is' [a-zA-Z0-9#x2D]+
## [37] MultiCharEsc ::= '\' [sSiIcCdDwW]