VMS Help SET, PROCESS, Qualifiers, /PARSE_STYLE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /PARSE_STYLE=(keyword)

    Allows a user to indicate how commands are to be parsed.

    Setting a particular parse style tells DCL how it should handle
    command syntax. User programs can also examine the state of this
    setting if they need to use different parse rules.

    The valid keywords for this qualifier are TRADITIONAL and
    EXTENDED. These keywords are mutually exclusive and cannot be
    negated.

    If the /PARSE_STYLE qualifier is not specified, the default is
    the TRADITIONAL format.

    Keyword     Explanation

    TRADITIONAL Indicates that commands should be examined using the
    (default)   former (prior to Version 7.2) rules for DCL syntax.
    EXTENDED    Indicates that commands should be examined using a
    (Alpha      syntax that allows ODS-5 file specifications.
    only)

    The main differences for DCL when EXTENDED parse rules are in
    effect are:

    o  Arguments to foreign commands are case preserved. You can get
       the command string by calling LIB$GET_FOREIGN. Note that at
       this time, C/C++ programs which use the argc/argv mechanism
       still have unquoted arguments in lowercase.

    o  Some characters that were previously treated as token
       delimiters are no longer delimiters. The pound sign (#),
       circumflex (^), and question mark (?) fall into this category.

    o  A circumflex (^) is an escape character, which can be used to
       indicate that the next character in the command string is to
       be treated as if it were quoted, thereby losing its syntactic
       significance.

    EXTENDED parsing also modifies DCL's rules for file
    specifications, that is, any item with a $FILE type in a Command
    Definition Language (.CLD) file:

    o  File specifications will not be in uppercase.

    o  Any number of commas (,) may be placed between directory
       delimiters ([] and <>).

    o  Directory file ID's (DIDs) can be included in the file
       specification.

    o  Any number of periods (.) or semi-colons (;) may be included
       in the file specification.

    Refer to the OpenVMS Guide to Extended File Specifications for
    more information.