The Eclipse IDE can be used to assist a user in the authoring of DFDL schemas.
See also Installing Eclipse.
DFDL extends a subset of XML Schema. Note however: an XML Schema is an XML document.
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This page contains instructions for setting up the Eclipse Integrated-Development-Environment (IDE), and to configure it's XML editing features so that they provide some level of support for authoring DFDL schemas. In theory, based on this, if you have some other favorite XML-Schema-Aware editing environment, you could figure out how to enable it to provide you similar DFDL schema authoring assistance.
Eclipse XML Settings
(Caveat: The menu locations often vary from one Eclipse release to the next.)
Following are steps to modify the eclipse XML settings to aid in the creation of DFDL schemas:
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