metasyntactic variable


n. A name used in examples and understood to stand for whatever thing is under discussion, or any random member of a class of things under discussion. The word foo is the canonical example. To avoid confusion, hackers never (well, hardly ever) use `foo' or other words like it as permanent names for anything. In filenames, a common convention is that any filename beginning with a metasyntactic-variable name is a scratch file that may be deleted at any time.

To some extent, the list of one's preferred metasyntactic variables is a cultural signature. They occur both in series (used for related groups of variables or objects) and as singletons. Here are a few common signatures:

foo, bar, baz, quux, quuux, quuuux...:
MIT/Stanford usage, now found everywhere (thanks largely to early versions of this lexicon!). At MIT (but not at Stanford), baz dropped out of use for a while in the 1970s and '80s. A common recent mutation of this sequence inserts qux before quux.
bazola, ztesch:
Stanford (from mid-'70s on).
foo, bar, thud, grunt:
This series was popular at CMU. Other CMU-associated variables include gorp.
foo, bar, fum:
This series is reported to be common at XEROX PARC.
fred, barney:
See the entry for fred. These tend to be Britishisms.
toto, titi, tata, tutu:
Standard series of metasyntactic variables among francophones.
corge, grault, flarp:
Popular at Rutgers University and among GOSMACS hackers.
zxc, spqr, wombat:
Cambridge University (England).
shme
Berkeley, GeoWorks, Ingres. Pronounced /shme/ with a short /e/.
foo, bar, zot
Helsinki University of Technology, Finland.
blarg, wibble
New Zealand
Of all these, only `foo' and `bar' are universal (and baz nearly so). The compounds foobar and `foobaz' also enjoy very wide currency.

Some jargon terms are also used as metasyntactic names; barf and mumble, for example. See also Commonwealth Hackish for discussion of numerous metasyntactic variables found in Great Britain and the Commonwealth.