Commit 74490e55 authored by Richard M. Stallman's avatar Richard M. Stallman
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*** empty log message ***

parent 1911e6e5
......@@ -32,9 +32,10 @@ the whole list.
Lists in Lisp are not a primitive data type; they are built up from
@dfn{cons cells}. A cons cell is a data object that represents an
ordered pair. It records two Lisp objects, one labeled as the @sc{car},
and the other labeled as the @sc{cdr}. These names are traditional; see
@ref{Cons Cell Type}. @sc{cdr} is pronounced ``could-er.''
ordered pair. It holds, or ``points to,'' two Lisp objects, one labeled
as the @sc{car}, and the other labeled as the @sc{cdr}. These names are
traditional; see @ref{Cons Cell Type}. @sc{cdr} is pronounced
``could-er.''
A list is a series of cons cells chained together, one cons cell per
element of the list. By convention, the @sc{car}s of the cons cells are
......@@ -82,10 +83,10 @@ made from two cons cells:
Each pair of boxes represents a cons cell. Each box ``refers to'',
``points to'' or ``contains'' a Lisp object. (These terms are
synonymous.) The first box, which is the @sc{car} of the first cons
cell, contains the symbol @code{tulip}. The arrow from the @sc{cdr} of
the first cons cell to the second cons cell indicates that the @sc{cdr}
of the first cons cell points to the second cons cell.
synonymous.) The first box, which describes the @sc{car} of the first
cons cell, contains the symbol @code{tulip}. The arrow from the
@sc{cdr} box of the first cons cell to the second cons cell indicates
that the @sc{cdr} of the first cons cell is the second cons cell.
The same list can be illustrated in a different sort of box notation
like this:
......@@ -668,8 +669,9 @@ different element.
@defun setcar cons object
This function stores @var{object} as the new @sc{car} of @var{cons},
replacing its previous @sc{car}. It returns the value @var{object}.
For example:
replacing its previous @sc{car}. In other words, it changes the
@sc{car} slot of @var{cons} to point to @var{object}. It returns the
value @var{object}. For example:
@example
@group
......@@ -770,7 +772,9 @@ x2: |
@defun setcdr cons object
This function stores @var{object} as the new @sc{cdr} of @var{cons},
replacing its previous @sc{cdr}. It returns the value @var{object}.
replacing its previous @sc{cdr}. In other words, it changes the
@sc{cdr} slot of @var{cons} to point to @var{object}. It returns the
value @var{object}.
@end defun
Here is an example of replacing the @sc{cdr} of a list with a
......@@ -797,7 +801,7 @@ x
You can delete elements from the middle of a list by altering the
@sc{cdr}s of the cons cells in the list. For example, here we delete
the second element, @code{b}, from the list @code{(a b c)}, by changing
the @sc{cdr} of the first cell:
the @sc{cdr} of the first cons cell:
@example
@group
......@@ -968,7 +972,7 @@ each time you run it! Here is what happens:
This function reverses the order of the elements of @var{list}.
Unlike @code{reverse}, @code{nreverse} alters its argument by reversing
the @sc{cdr}s in the cons cells forming the list. The cons cell that
used to be the last one in @var{list} becomes the first cell of the
used to be the last one in @var{list} becomes the first cons cell of the
value.
For example:
......@@ -985,7 +989,7 @@ x
@result{} (4 3 2 1)
@end group
@group
;; @r{The cell that was first is now last.}
;; @r{The cons cell that was first is now last.}
x
@result{} (1)
@end group
......@@ -1249,7 +1253,7 @@ for another way to add an element to a list stored in a variable.
An @dfn{association list}, or @dfn{alist} for short, records a mapping
from keys to values. It is a list of cons cells called
@dfn{associations}: the @sc{car} of each cell is the @dfn{key}, and the
@dfn{associations}: the @sc{car} of each cons cell is the @dfn{key}, and the
@sc{cdr} is the @dfn{associated value}.@footnote{This usage of ``key''
is not related to the term ``key sequence''; it means a value used to
look up an item in a table. In this case, the table is the alist, and
......
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