blurgle /bler'gl/ n.
[UK] Spoken metasyntactic variable, to
indicate some text that is obvious from context, or which is
already known. If several words are to be replaced, blurgle may
well be doubled or tripled. "To look for something in several
files use `grep string blurgle blurgle'." In each case, "blurgle
blurgle" would be understood to be replaced by the file you
wished to search. Compare mumble,
sense 7.
Node:BNF, Next:boa, Previous:blurgle, Up:= B
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BNF /B-N-F/ n.
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.