lisp-indent-function
lisp-indent-function is a compiled Lisp function in `lisp-mode.el
'.
(lisp-indent-function INDENT-POINT STATE)
This function is the normal value of the variable `lisp-indent-function'.
The function `calculate-lisp-indent' calls this to determine
if the arguments of a Lisp function call should be indented specially.
INDENT-POINT is the position at which the line being indented begins.
Point is located at the point to indent under (for default indentation);
STATE is the `parse-partial-sexp' state for that position.
If the current line is in a call to a Lisp function that has a non-nil
property `lisp-indent-function' (or the deprecated `lisp-indent-hook'),
it specifies how to indent. The property value can be:
* `defun', meaning indent `defun'-style
(this is also the case if there is no property and the function
has a name that begins with "def", and three or more arguments);
* an integer N, meaning indent the first N arguments specially
(like ordinary function arguments), and then indent any further
arguments like a body;
* a function to call that returns the indentation (or nil).
`lisp-indent-function' calls this function with the same two arguments
that it itself received.
This function returns either the indentation to use, or nil if the
Lisp function does not specify a special indentation.