XML Schema compact syntax (XSCS) is an alternative text representation of XML Schema that is more compact and readable than the ordinary XML format. For example, compare:

Compact Syntax

element recording_technique restricts bmtl:vocab-type {
    attribute domain {xs:token} = "trace.data class"

Full XML Syntax

<xs:element name="recording_technique">
   <xs:complexType>
      <xs:complexContent>
	 <xs:restriction base="bmtl:vocab-type">
	    <xs:attribute name="domain" type="xs:token"
			  fixed="trace.data class"/>
	 </xs:restriction>
      </xs:complexContent>
   </xs:complexType>
</xs:element>

More examples are available in this introductory article, and the authoritative specification is here.

BrainML.org accepts schemas in either compact or regular formats, and makes all schemas available in both. This capability is based on an open source tool called xsconv which converts losslessly between the two. This is a Java tool available for download. (See README.txt in download for usage instructions.) This tool is based on the code for "xsc.jar" by Erik Wilde and Kilian Stillhard available here.

Included in the above download is an Emacs mode for viewing/editing XML Schema Compact Syntax.