ExpressionML (.xml)

Import and Export fully support the ExpressionML format.

Background & Context

- MIME type: text/xmlWolfram Language ExpressionML format.
- Represents an arbitrary Wolfram Language expression as XML.
- Used for the exchange of general expressions between the Wolfram System and other applications.
- Plain text file, normally encoded as UTF-8.
- Developed in 2002 by Wolfram Research.

Import & Export

Import["file.xml"] imports an ExpressionML file and returns an expression.
Export["file.xml",expr,"ExpressionML"] exports an arbitrary expression to XML.
Import["file.xml"] reads an XML file that holds ExpressionML data and converts it to the corresponding Wolfram Language expression.
When reading XML, Import automatically recognizes the ExpressionML format. Generic XML content will be imported as an XMLObject expression.
Export["file.xml",expr,"ExpressionML"] converts an arbitrary Wolfram Language expression to the corresponding ExpressionML data structure and writes it to an XML file.
Export["file.xml",XMLObject[…]] converts a symbolic XML expression to generic XML.
Import["file.xml",elem] imports the specified element from an ExpressionML file.
Import["file.xml",{{elem₁,elem₂,…}}] imports multiple elements.
The import format can be specified with Import["file","ExpressionML"] or Import["file",{"ExpressionML",elem,…}].
Export["file.xml",expr,elem] creates an ExpressionML file by treating expr as specifying element elem.
Export["file.xml",{expr₁,expr₂,…},{{elem₁,elem₂,…}}] treats each expr_i as specifying the corresponding elem_i.
Export["file.xml",expr,opt₁->val₁,…] exports expr with the specified option elements taken to have the specified values.
Export["file.xml",{elem₁->expr₁,elem₂->expr₂,…},"Rules"] uses rules to specify the elements to be exported.
The export format can be explicitly specified in the form Export["file",expr,"ExpressionML"] or Export["file",expr,{"ExpressionML",elems}].
See the reference pages for full general information on Import and Export.
ImportString and ExportString support the ExpressionML format.

Import Elements

General Import elements:

	"Elements"	list of elements and options available in this file
	"Rules"	full list of rules for each element and option
	"Options"	list of rules for options, properties, and settings

Data representation elements:

	"Boxes"	ExpressionML typeset as a Wolfram Language box expression
	"Expression"	arbitrary Wolfram Language expression
	"HeldExpression"	unevaluated expression
	"XMLObject"	ExpressionML as a symbolic XML expression
	"XMLElement"	nested XMLElement objects

Import and Export use the "Expression" element by default.

Examples

Basic Examples (1)

Convert a mathematical expression to the ExpressionML format:

Import automatically recognizes the ExpressionML format when reading XML data:

Show the available Import elements:

Convert ExpressionML to an evaluated expression:

Import without evaluating:

Convert ExpressionML to a Wolfram Language typesetting expression:

Import ExpressionML to a complete symbolic XML expression:

Import ExpressionML to a symbolic XML fragment:

Introduced in 2002

(4.2)

Updated in 2007

(6.0)

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