BNF

   1.  [techspeak]  Acronym  for Backus Normal Form (later retronymed to
   Backus-Naur  Form  because  BNF  was  not  in  fact a normal form), a
   metasyntactic  notation  used  to  specify  the syntax of programming
   languages,  command  sets,  and  the  like.  Widely used for language
   descriptions  but seldom documented anywhere, so that it must usually
   be  learned  by  osmosis  from other hackers. Consider this BNF for a
   U.S. postal address:

    <postal-address> ::= <name-part> <street-address> <zip-part>
    <personal-part> ::= <name> | <initial> "."
    <name-part> ::= <personal-part> <last-name> [<jr-part>] <EOL>
                  | <personal-part> <name-part>
    <street-address> ::= [<apt>] <house-num> <street-name> <EOL>
    <zip-part> ::= <town-name> "," <state-code> <ZIP-code> <EOL>

   This  translates  into  English  as:  "A postal-address consists of a
   name-part,  followed by a street-address part, followed by a zip-code
   part.  A  personal-part consists of either a first name or an initial
   followed  by  a  dot. A name-part consists of either: a personal-part
   followed by a last name followed by an optional jr-part (Jr., Sr., or
   dynastic  number)  and  end-of-line, or a personal part followed by a
   name  part  (this  rule  illustrates  the  use  of recursion in BNFs,
   covering  the  case of people who use multiple first and middle names
   and/or  initials). A street address consists of an optional apartment
   specifier,  followed by a street number, followed by a street name. A
   zip-part  consists of a town-name, followed by a comma, followed by a
   state  code, followed by a ZIP-code followed by an end-of-line." Note
   that  many  things  (such as the format of a personal-part, apartment
   specifier,  or  ZIP-code) are left unspecified. These are presumed to
   be  obvious  from  context  or  detailed  somewhere  nearby. See also
   {parse}.

   2. Any of a number of variants and extensions of BNF proper, possibly
   containing  some  or all of the {regexp} wildcards such as * or +. In
   fact  the example above isn't the pure form invented for the Algol-60
   report;  it  uses [], which was introduced a few years later in IBM's
   PL/I definition but is now universally recognized.

   3.  In  {science-fiction fandom}, a `Big-Name Fan' (someone famous or
   notorious).  Years  ago  a fan started handing out black-on-green BNF
   buttons  at  SF  conventions;  this  confused  the  hacker contingent
   terribly.

[glossary]
[Reference(s) to this entry by made by: {EOL}]