MFTL /M-F-T-L/ [abbreviation: `My Favorite Toy Language'] 1.

HomeFortune CookiesJargon File


[abbreviation: `My Favorite Toy Language']
1. adj. Describes a talk on a programming language design that
is heavy on the syntax (with lots of BNF), sometimes even talks
about semantics (e.g., type systems), 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. n. Describes a language about which the
developers are passionate (often to the point of proselytic 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 (compiled) language that cannot even be used to write
its own compiler is beneath contempt. (The qualification has
become necessary because of the increasing popularity of
interpreted languages like Perl and Python. See
break-even point.

(On a related note, 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? (See toolsmith.)
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".)