Is there a reason that we can't put an unescaped ampersand in XML

Question

My customer wants to write my xml file as <name>Smith & Jones</name>, not <name>Smith &amp; Jones</name>.

I can't find a quality reference discussing this.

Answer 1

From the XML specification (§2.4):

The ampersand character (&) and the left angle bracket (<) may appear in their literal form only when used as markup delimiters, or within a comment, a processing instruction, or a CDATA section. They are also legal within the literal entity value of an internal entity declaration; see "4.3.2 Well-Formed Parsed Entities". If they are needed elsewhere, they must be escaped using either numeric character references or the strings "&" and "<" respectively.

Since this circumstance fits into none of the stated categories, it is illegal.

Answer 2

Use the CDDATA tag to insert these characters within the XML tags without XML parsing them:

<name>Smith & Jones</name>

becomes

<name><![CDATA[ Smith & Jones ]]></name>

this way you can also put plain html withing xml.

example: http://www.w3schools.com/xml/xml_cdata.asp