Relax NG non-XML Grammar

source: relaxNG.g

topLevel: decl * ( pattern
| grammar ) END
decl: ( "namespace" identifier "=" ( literal
| "inherit" ) )
| ( "default" "namespace" [ identifier ] "=" ( literal
| "inherit" ) )
| ( "datatypes" identifier "=" literal )
pattern: UnaryExpr [ ( "\\|" UnaryExpr ) +
| ( "," UnaryExpr ) +
| ( "&" UnaryExpr ) + ]
UnaryExpr: PrimaryExpr [ "\\*"
| "\\+"
| "\\?" ]
PrimaryExpr: "empty"
| "text"
| "notAllowed"
| ( "element" NameClass ₀ "{" pattern "}" )
| ( "attribute" NameClass ₁ "{" pattern "}" )
| ( "list" "{" pattern "}" )
| ( "mixed" "{" pattern "}" )
| ( "grammar" "{" grammar "}" )
| ( "\\(" pattern "\\)" )
| ( "externalRef" literal [ inherit ] )
| ( "parent" ref )
| ref
| datatypeValue
| ( datatypeName [ ( params [ Except ] )
| Except
| datatypeValue ] )
Except: "-" PrimaryExpr
NameClass _inAttr: PrimaryNameClass _inAttr [ ( "\\|" PrimaryNameClass _inAttr ) * ]
PrimaryNameClass _inAttr: UnprefixedNameClass _inAttr
| PrefixedNameClass
| AnyNameClass _inAttr
| NsNameClass _inAttr
| ParenNameClass _inAttr
UnprefixedNameClass _inAttr: identifier
PrefixedNameClass: CName
NsNameClass _inAttr: nsName [ "-" PrimaryNameClass _inAttr ]
AnyNameClass _inAttr: "\\*" [ "-" PrimaryNameClass _inAttr ]
ParenNameClass _inAttr: "\\(" NameClass _inAttr "\\)"
ref: identifierNotKeyword
datatypeName: CName
| "string"
| "token"
datatypeValue: literal
params: "{" ( identifier "=" literal ) + "}"
grammar: ( definition
| include ) +
definition: defLHS pattern
defLHS: ( "start" ( "="
| "\\|="
| "&=" ) )
| identDEF
include: "include" literal [ inherit ] [ "{" definition * "}" ]
inherit: "inherit" "=" identifier
literal: literal1
| literal2