html5ever
macro_rules! namespace_prefix { ( "mathml" ) => { ... }; ( "xmlns" ) => { ... }; ( "html" ) => { ... }; ( "xml" ) => { ... }; ( "xlink" ) => { ... }; ( "*" ) => { ... }; ( "svg" ) => { ... }; ( "" ) => { ... }; }
Takes a namespace prefix string and returns its key in a string cache.