Come posso includere un carattere di e commerciale (&) in un documento XML?

Question

Come posso inserire un simbolo & in un attributo di un tag XML pur mantenendo valido il codice XML?

<?xml version="1.0" ?> 
<a text="b&c"/> 

Quando uso W3School's validator, ottengo l'errore:

EntityRef: expecting ' ; '

Answer 1

utilizzare un riferimento di carattere per rappresentarla: &

Vedere il specification:

The ampersand character (&) and the left angle bracket (<) MUST NOT appear in their literal form, except when used as markup delimiters, or within a comment, a processing instruction, or a CDATA section. If they are needed elsewhere, they MUST be escaped using either numeric character references or the strings " & " and " < " respectively. The right angle bracket (>) may be represented using the string " > ", and MUST, for compatibility, be escaped using either " > " or a character reference when it appears in the string " ]]> " in content, when that string is not marking the end of a CDATA section.