The IsProcessingInstruction(expr) command tests whether a Maple expression expr is an XML processing instruction data structure. If expr is an XML processing instruction data structure, the value true is returned. Otherwise, false is returned.

Such expressions can be encountered in XML documents that are read from external sources, or can be generated programmatically by using the XMLTools[XMLProcessingInstruction] constructor.

Every valid XML document begins with the processing instruction $<\&quest;\mathrm{xml\; version}=1\&period;0\&quest;>$.

$\mathrm{with}\left(\mathrm{XMLTools}\right)\&colon;$

$\mathrm{IsProcessingInstruction}\left(\mathrm{XMLElement}\left(''a''\&comma;\left[''b''=''c''\right]\&comma;''d''\&comma;''e''\right)\right)$

$\mathrm{false}$

$\mathrm{IsProcessingInstruction}\left(\mathrm{XMLProcessingInstruction}\left(''xml''\&comma;''version=1.0''\right)\right)$

$\mathrm{true}$