The Table-Driven Finite-State Parser routine is a general-
    purpose, table-driven parser implemented as a finite-state
    automaton, with extensions that make it suitable for a wide
    range of applications. It parses a string and returns a message
    indicating whether or not the input string is valid.

    LIB$T[ABLE_]PARSE is called with the address of an argument
    block, the address of a state table, and the address of a keyword
    table. The input string is specified as part of the argument
    block.

    The LIB$ facility supports the following two versions of the
    Table-Driven Finite-State Parser:

    LIB$TPARSE       Available on VAX systems.
                     LIB$TPARSE is available on Alpha and I64
                     systems in translated form. In this form, it
                     is applicable to translated VAX images only.
    LIB$TABLE_PARSE  Available on VAX, Alpha, and I64 systems.

    LIB$TPARSE and LIB$TABLE_PARSE differ mainly in the way they pass
    arguments to action routines.

    The term LIB$T[ABLE_]PARSE is used here to describe concepts that
    apply to both LIB$TPARSE and LIB$TABLE_PARSE.

    Format

      LIB$TPARSE/LIB$TABLE_PARSE  argument-block ,state-table

                                  ,key-table