isearch-mode

isearch-mode is a compiled Lisp function in `isearch.el'.

(isearch-mode FORWARD &optional REGEXP OP-FUN RECURSIVE-EDIT WORD)

Start Isearch minor mode.
It is called by the function `isearch-forward' and other related functions.

The non-nil arg FORWARD means searching in the forward direction.

The non-nil arg REGEXP does an incremental regular expression search.

The arg OP-FUN is a function to be called after each input character
is processed. (It is not called after characters that exit the search.)

When the arg RECURSIVE-EDIT is non-nil, this function behaves modally and
does not return to the calling function until the search is completed.
To behave this way it enters a recursive-edit and exits it when done
isearching.

The arg WORD, if t, does incremental search for a sequence of words,
ignoring punctuation. If the value is a function, it is called to
convert the search string to a regexp used by regexp search functions.