The ITP DID language obeys the same lexical rules as the ITP Language. This means that the language is free-format. Tabs, end-of-lines, end-of-paragraphs and spaces are all treated as white space. ITP interprets multiple white spaces as a single one. You can add comments to the DID Document. You should put comments between (* and *). ITP also treats a comment as a white space.
Names of ITP identifiers in the ITP DID language should start with an uppercase character and can be followed by lowercase characters, uppercase characters digits or underscores '_'. The identifiers defined in the DID Language are the names of Entries and Fields that a Model Developers uses in a Model Document.
You can use __INC to include subdocuments in your DID Document; you can for example store every DID Module definition in it's own subdocument.
ITP ignores all text before the DEFINE_DID statement; it does not generate error messages for this text. __INC directions are however evaluated throughout the whole document. This is also true for __INC directions before the DEFINE_DID statement and in comments.
When your DID Document only consists of __INC directions for both the DID definition and the DID Module definitions, you might get a strange error message when you have no include path setting. Since ITP will not resolve the subdocuments, it will not encounter a DEFINE_DID and therefore ignore all text in the DID Document.