[racket] Quick question - use of ". -> ." synatx

From: Casey Klein (clklein at eecs.northwestern.edu)
Date: Sat Dec 25 06:56:03 EST 2010

On Sat, Dec 25, 2010 at 1:48 AM, Scott McLoughlin <scottmcl66 at gmail.com> wrote:
> Couldn't find docs on this syntax form using regular
> docs search.

I don't know how to find it with search either, but here it is.


"If the reader finds three or more data between the matching
parentheses, and if a pair of delimited .s surrounds any other than
the first and last elements, the result is a list containing the
element surrounded by .s as the first element, followed by the others
in the read order. This convention supports a kind of infix notation
at the reader level."

In other words, this syntax isn't specific to contracts. Surrounding
anything with dots is the same as placing it to the immediate right of
the nearest enclosing left paren.

> '(a . b . c)
'(b a c)

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