Examine individual changes

'{{Distinguish|FUBAR}} {{Other uses}} The terms '''foobar''', '''foo''', '''bar''', and '''baz''' are sometimes used as [[placeholder name]]s (also referred to as [[metasyntactic variable]]s) in [[computer programming]] or computer-related documentation.<ref name="rfc3092" /> They have been used to name entities such as [[Variable (computer science)|variable]]s, [[Function (computer science)|functions]], and [[command (computing)|command]]s whose purpose is unimportant and serve only to demonstrate a concept. The words themselves have no meaning in this usage. ''Foobar'' is sometimes used alone; ''foo'', ''bar'', and ''baz'' are sometimes used in that order, when multiple entities are needed. The usage in [[computer programming]] examples and [[pseudocode]] varies; in certain circles, it is used extensively, but many prefer descriptive names, while others prefer to use single letters. [[Eric S. Raymond]] has called it an "important hackerism" alongside [[kludge]] and [[cruft]].<ref name="Raymond">{{cite book|url=http://books.google.com/books?id=g80P_4v4QbIC&lpg=PP1&pg=PA5|title=The New Hacker's Dictionary|author=[[Eric S. Raymond]]|publisher=[[MIT Press]]|year=1996|isbn=0262680920}}</ref> == History and etymology == The origins of the terms are not known with certainty, and several anecdotal theories have been advanced to identify them. ''Foobar'' may have derived from the military acronym [[FUBAR]] and gained popularity due to the fact that it is pronounced the same. In this meaning it also can derive from the German word ''furchtbar'', which means ''awful'' and ''terrible'' and described the circumstances of the [[World War II|Second World War]]. American soldiers in Germany had problems with the pronunciation of the German word and used it in a simplified form.{{Citation needed|date=April 2010}} ''FOO'' is an abbreviation of [[Forward Observation Officer]], a [[British Army]] term in use as early as the [[World War I|First World War]].<ref>[http://www.1914-1918.net/Diaries/wardiary-118siege.htm Extract from War Diary of 118th Siege Battery WO95/322], 1914-1918.net</ref> The etymology of ''foo'' is explored in the [[Internet Engineering Task Force]] (IETF) [[Request for Comments]] 3092, which notes usage of ''foo'' in 1930s cartoons including ''[[List of Daffy Duck cartoons|The Daffy Duck]]'' and comic strips, especially ''[[Smokey Stover]]'' and ''[[Pogo (comics)|Pogo]]''. From there the term migrated into military slang, where it merged with FUBAR.<ref name="rfc3092">{{cite web|url=http://www.ietf.org/rfc/rfc3092.txt|title=Etymology of "Foo"|author=D. Eastlake III et al.|year=2001|publisher=[[Internet Engineering Task Force]]|accessdate=2007-11-05}}</ref> "Bar" as the second term in the series may have developed in electronics, where a digital signal which is considered "on" with a negative or zero-voltage condition is identified with a horizontal bar over the signal label; the notation for an inverted signal ''foo'' would then be pronounced "foo bar".{{Citation needed|date=May 2009}} "Foo" has sometimes been expanded as the [[backronym]] "for once only". The use of ''foo'' in hacker and eventually in programming context may have begun in MIT's [[Tech Model Railroad Club]] (TMRC). In the complex model system there were [[scram]] switches located at numerous places around the room that could be thrown if something undesirable was about to occur, such as a train going full-bore at an obstruction. Another feature of the system was a digital clock on the dispatch board. When someone hit a scram switch the clock stopped and the display was replaced with the word "FOO"; at TMRC the scram switches are therefore called "Foo switches". Because of this an entry in the 1959 Dictionary of the TMRC Language went something like this: "FOO: The first syllable of the misquoted sacred chant phrase '[[Om mani padme hum|foo mane padme hum]].' Our first obligation is to keep the foo counters turning."<ref>{{cite web |url=http://www.computer-dictionary-online.org/?q=foo |title=Computer Dictionary Online}}, computer-dictionary-online.org</ref> One book{{Citation needed|date=July 2010}} describing the MIT train room describes two buttons by the door: labelled foo and bar. These were general purpose buttons and were often re-purposed for whatever fun idea the MIT hackers had at the time. Hence the adoption of foo and bar as general purpose variable names. The term ''foobar'' was propagated through computer science circles in the 1960s and early 1970s by system manuals from [[Digital Equipment Corporation]].{{Citation needed|date=May 2009}} ''Foobar'' was used as a variable name in the [[Fortran]] code of [[Colossal Cave Adventure]] (1977 Crowther and Woods version). The variable FOOBAR was used to contain the player's progress in saying the magic phrase "Fee Fie Foe Foo". ==Usage in code== The terms are very often used in programming examples, much like the [[Hello World]] program is commonly used as an introduction. For example, ''foo'' and ''bar'' might be used to illustrate a simple string concatenation: <source lang="c"> // C code #include <stdio.h> int main() { char foo[] = "Hello,"; char bar[] = "World!"; printf("%s %s\n", foo, bar); return 0; } </source> <source lang="cpp"> // C++ code #include <iostream> using namespace std; int main() { char foo[] = "Hello,"; char bar[] = "World!"; cout << foo << " " << bar << endl; return 0; } </source> ==Usage in culture== ''$foo'' is the name of a [[Perl]] programming magazine,<ref>[http://foo-magazin.de/ Foo-magazin.de] {{de icon}}</ref> and [[Foo Camp]] is an annual [[hacker convention]] (the name is also a [[backronym]] for Friends of [[O'Reilly Media|O'Reilly]], the event's sponsor). During the [[United States v. Microsoft]] trial, some evidence was presented that Microsoft had tried to use the [[Web Services Interoperability]] organization as a means to stifle competition, including e-mails in which top executives including [[Bill Gates]] referred to the WS-I using the codename "foo".<ref>[http://www.news.com/Microsoft-ploy-to-block-Sun-exposed/2100-1001_3-912906.html Microsoft ploy to block Sun exposed], news.com</ref> ==Criticism== {{Weasel|date=August 2010}} Some people {{Who|date=August 2010}} believe that foo-bar examples are useless and should not be used in any high quality source. In many cases authors of computer programming books try to make difficult design patterns look simple by using foo-bar conventions. Unfortunately it rarely helps to show the true purpose or meaning of the solution. Foo-bar is not helpful{{Citation needed|date=August 2010}} to understand difficult problems as in itself it does not mean anything.{{Citation needed|date=July 2010}} Serious authors should consider making an effort to find a suitable example and present the problem and solution using it, not the meaningless foo bar construct.{{Citation needed|date=August 2010}} In this sense foo bar seems suitable only for the most simplistic examples. Beyond a certain point it can be considered as laziness.{{Citation needed|date=July 2010}} == See also == * [[BarCamp]], an international network of user generated conferences * [[Foo Camp]], an annual hacker event hosted by publisher O'Reilly Media * [[FUBAR]], a homophonous acronym * [[John Doe]], a placeholder name for a male party, in a legal action, case or discussion, whose true identity is either unknown or must be withheld for legal reasons * [[Lorem ipsum]], the name given to commonly used placeholder text * [[Placeholder name]] == References == {{Reflist}} == External links == {{Wiktionary|foobar}} *[http://tools.ietf.org/html/rfc3092 RFC3092 Etymology of "Foo"], tools.ietf.org *[http://foldoc.org/index.cgi?query=foo The Free Online Dictionary of Computing entry on "foo"], foldoc.org *[http://www.catb.org/~esr/jargon/html/F/foobar.html The Jargon File entry on "foobar"], catb.org *[http://www.foobar2000.org/ Foobar2000 is an advanced audio player for the Windows platform], foobar2000.org *RFC 1639 – FTP Operation Over Big Address Records (FOOBAR) [[Category:Placeholder names]] [[Category:Variable (computer programming)]] [[da:Foo (data)]] [[de:Fubar]] [[es:Foo]] [[fr:Variable métasyntaxique]] [[it:Foo]] [[nl:Foobar]] [[ja:Foobar]] [[no:Foo]] [[ru:Foobar]] [[sl:Foo]] [[fi:Foo]] [[sv:Metavariabel]] [[vi:Foo]] [[zh:Foobar]]'