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Improve documentation of cl-reduce

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* doc/misc/cl.texi (Mapping over Sequences): Change the
explanation of 'cl-reduce' so you don't need to have a major in
mathematics to understand it.  (Bug#24014)
This commit is contained in:
Stefan Kangas
2021-10-23 19:20:31 +02:00
parent ef37a86cac
commit 43914ab01f
1 changed files with 7 additions and 3 deletions
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doc/misc/cl.texi
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@@ -3364,9 +3364,13 @@ true for all elements.
@end defun
@defun cl-reduce function seq @t{&key :from-end :start :end :initial-value :key}
This function combines the elements of @var{seq} using an associative
binary operation. Suppose @var{function} is @code{*} and @var{seq} is
the list @code{(2 3 4 5)}. The first two elements of the list are
This function returns the result of calling @var{function} on the
first and second element of @var{seq}, then calling @var{function}
with that result and the third element of @var{seq}, then with that
result and the third element of @var{seq}, etc.
Here is an example. Suppose @var{function} is @code{*} and @var{seq}
is the list @code{(2 3 4 5)}. The first two elements of the list are
combined with @code{(* 2 3) = 6}; this is combined with the next
element, @code{(* 6 4) = 24}, and that is combined with the final
element: @code{(* 24 5) = 120}. Note that the @code{*} function happens