29 lines
1.8 KiB
Plaintext
29 lines
1.8 KiB
Plaintext
metasyntactic variable
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n. A name used in examples and understood to stand for whatever thing is
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under discussion, or any random member of a class of things under
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discussion. The word foo is the canonical example. To avoid confusion,
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hackers never (well, hardly ever) use foo or other words like it as
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permanent names for anything. In filenames, a common convention is that any
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filename beginning with a metasyntactic-variable name is a scratch file that
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may be deleted at any time. Metasyntactic variables are so called because
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(1) they are variables in the metalanguage used to talk about programs etc;
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(2) they are variables whose values are often variables (as in usages like
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the value of f(foo,bar) is the sum of foo and bar ). However, it has been
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plausibly suggested that the real reason for the term metasyntactic variable
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is that it sounds good. To some extent, the list of one's preferred
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metasyntactic variables is a cultural signature. They occur both in series
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(used for related groups of variables or objects) and as singletons. Here
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are a few common signatures: foo , bar , baz , quux , quuux, quuuux...:
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MIT/Stanford usage, now found everywhere (thanks largely to early versions
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of this lexicon!). At MIT (but not at Stanford), baz dropped out of use for
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a while in the 1970s and '80s. A common recent mutation of this sequence
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inserts qux before quux. bazola, ztesch: Stanford (from mid-'70s on). foo ,
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bar , thud, grunt: This series was popular at CMU. Other CMU-associated
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variables include gorp. foo , bar , bletch: Waterloo University. We are
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informed that the CS club at Waterloo formerly had a sign on its door
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reading Ye Olde Foo Bar and Grill ; this led to an attempt to establish
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grill as the third metasyntactic variable, but it never caught on. foo ,
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bar , fum: This series is reported to be common at XEROX PARC.
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