/sys$common/syshlp/helplib.hlb MACRO, VAX MACRO Assembler, Directives, .IRPC  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Similar to .IRP except that .IRPC permits single-character
    substitution rather than argument substitution.

            .IRPC symbol, <string>
                 ...
                range
                 ...
            .ENDR

           symbol

    A formal argument that is successively replaced  with  the
    specified characters  enclosed  in  angle  brackets.   If no formal
    argument is specified, the assembler displays an error message.

    <string>

    A sequence of characters enclosed in angle brackets and used  in
    the expansion  of  the  indefinite  repeat  range.   Although  the
    angle brackets are  required  only  when  the  string  contains
    separating characters, their use is recommended for legibility.

    range

    The block of source text to be repeated once for each occurrence of
    a character  in  the list.  The range can contain macro definitions
    and repeat ranges.

    On each iteration of the indefinite repeat range, the formal
    argument is  replaced  with each successive character in the
    specified string. The .ENDR directive specifies the end of the
    range.