资料来源 : Free On-Line Dictionary of Computing

My Favourite Toy Language
     
         (MFTL) Describes a talk on a {programming
        language} design that is heavy on {syntax} (with lots of
        {BNF}), sometimes even talks about {semantics} (e.g. {type
        system}s), but rarely, if ever, has any content (see
        {content-free}).  More broadly applied to talks - even when
        the topic is not a programming language --- in which the
        subject matter is gone into in unnecessary and meticulous
        detail at the sacrifice of any conceptual content.  "Well, it
        was a typical MFTL talk".
     
        2. A language about which the developers are passionate (often
        to the point of prosyletic zeal) but no one else cares about.
        Applied to the language by those outside the originating
        group.  "He cornered me about type resolution in his MFTL."
     
        The first great goal in the mind of the designer of an MFTL is
        usually to write a compiler for it, then bootstrap the design
        away from contamination by lesser languages by writing a
        compiler for it in itself.  Thus, the standard put-down
        question at an MFTL talk is "Has it been used for anything
        besides its own compiler?".  On the other hand, a language
        that *cannot* be used to write its own compiler is beneath
        contempt.
     
        {Doug McIlroy} once proposed a test of the generality and
        utility of a language and the {operating system} under which
        it is compiled: "Is the output of a {Fortran} program
        acceptable as input to the Fortran compiler?"  In other words,
        can you write programs that write programs?  Alarming numbers
        of (language, OS) pairs fail this test, particularly when the
        language is Fortran.  Aficionados are quick to point out that
        {Unix} (even using Fortran) passes it handily.  That the test
        could ever be failed is only surprising to those who have had
        the good fortune to have worked only under modern systems
        which lack OS-supported and -imposed "file types".
     
        See {break-even point}, {toolsmith}.
     
        (1995-03-07)