I am implementing dfdl:textNumberPattern characters V and E for Apache Daffodil.

The DFDL Spec says (Section 13.6.1.1) 

It is a Schema Definition Error if any symbols other than "0", "1" through "9" or # are used in the vpinteger region of the pattern.

Note that the vpitneger region of the pattern excludes the leading and/or trailing sign indicator characters which are the prefix and suffix. 

The prefix and suffix can contain any character except the special characters of the pattern language. 

Later in the section the spec has a number of detailed statements that are subsumed by the above I believe.

  • A pattern with a V symbol must not have @ or * symbols.
  • A pattern with P symbols must not have @ or E or * symbols.

So those latter 2 statements could be omitted since @ and * are "special characters" so aren't allowed in the prefix/suffix, and per above stipulation can't be in the vpinteger region either.

Can't we simplify and just say a pattern with V or P cannot have any special characters other than 0-9 and # ?

Mike Beckerle 
Apache Daffodil PMC | daffodil.apache.org
OGF DFDL Workgroup Co-Chair | www.ogf.org/ogf/doku.php/standards/dfdl/dfdl
Owl Cyber Defense | www.owlcyberdefense.com