Short for '''LIS'''t '''P'''rocessing.

A modern dialect is [Scheme]--although that identification is about as
incendiary in some circles as the observation that political, not
linguistic, markers separate Serbia from Croatia.

See [Tcl and LISP] or [Playing LISP].

Good LISP reading:  http://www.paulgraham.com/onlisptext.html , http://www.norvig.com/paip.html .
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On Tcl: "No question but that real lisps are more powerful than this bastard child
of lisp and awk, but for what it does it does a better job than either
parent. Which is all you need to ask of it." (Peter da Silva, 1994 [http://www.vanderburg.org/Tcl/war/0066.html])
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How close is the correspondence?

[[ ... ]] maps closely to ( ... )

{ ... } seems to be '( ... )

The difference (apart from expr, of course) is more in how words are grouped - in Lisp they form a list of tokens, not a string.  So manipulating expressions "as text" is done by manipulating tokens in macros.  And I'm at a bit of a loss to explain $...

[RS]: See (and maybe add to) [Tcl in comparison]
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John McCarthy (father of Lisp), LISP-Notes on its past and future-1980 ([http://www-formal.stanford.edu/jmc/lisp20th/node5.html#SECTION00050000000000000000]):
"It seems to me that LISP will probably be superseded for many purposes by a language that does to LISP what LISP does to machine language. Namely it will be a higher level language than LISP that, like LISP and machine language, can refer to its own programs." Does Tcl fit that description? I think so! ([RS])
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[Category Language]
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