Consider a toy variant of XHTML named ToyXHTML whose syntax may be described as follows:
Formalize the syntax of ToyXHTML using your favorite schema language.
datatypes xs = "http://www.w3.org/2001/XMLSchema-datatypes" element doc { ( element p { ( text | element em { text } | element a { (attribute name { text } | attribute href { xs:anyURI }), text } )* } | element h1 { text } )* }