Here is a brief summary of some recently introduced functions.
car
cdr
car
returns the first element of a list; cdr
returns the
second and subsequent elements of a list.
For example:
(car '(1 2 3 4 5 6 7)) ⇒ 1 (cdr '(1 2 3 4 5 6 7)) ⇒ (2 3 4 5 6 7)
cons
cons
constructs a list by prepending its first argument to its
second argument.
For example:
(cons 1 '(2 3 4)) ⇒ (1 2 3 4)
funcall
funcall
evaluates its first argument as a function. It passes
its remaining arguments to its first argument.
nthcdr
Return the result of taking CDR n times on a list. The “rest of the rest”, as it were.
For example:
(nthcdr 3 '(1 2 3 4 5 6 7)) ⇒ (4 5 6 7)
setcar
setcdr
setcar
changes the first element of a list; setcdr
changes the second and subsequent elements of a list.
For example:
(setq triple (list 1 2 3)) (setcar triple '37) triple ⇒ (37 2 3) (setcdr triple '("foo" "bar")) triple ⇒ (37 "foo" "bar")
progn
Evaluate each argument in sequence and then return the value of the last.
For example:
(progn 1 2 3 4) ⇒ 4
save-restriction
Record whatever narrowing is in effect in the current buffer, if any, and restore that narrowing after evaluating the arguments.
search-forward
Search for a string, and if the string is found, move point. With a
regular expression, use the similar re-search-forward
.
(See Regular Expression Searches, for an
explanation of regular expression patterns and searches.)
search-forward
and re-search-forward
take four
arguments:
nil
or an
error message.
kill-region
delete-and-extract-region
copy-region-as-kill
kill-region
cuts the text between point and mark from the
buffer and stores that text in the kill ring, so you can get it back
by yanking.
copy-region-as-kill
copies the text between point and mark into
the kill ring, from which you can get it by yanking. The function
does not cut or remove the text from the buffer.
delete-and-extract-region
removes the text between point and
mark from the buffer and throws it away. You cannot get it back.
(This is not an interactive command.)