Evaluate the top-level form containing point, or after point.
If the current defun is actually a call to `defvar' or `defcustom',
evaluating it this way resets the variable using its initial value
expression even if the variable already has some other value.
(Normally `defvar' and `defcustom' do not alter the value if there
already is one.) In an analogous way, evaluating a `defface'
overrides any customizations of the face, so that it becomes
defined exactly as the `defface' expression says.
If `eval-expression-debug-on-error' is non-nil, which is the default,
this command arranges for all errors to enter the debugger.
With a prefix argument, instrument the code for Edebug.
If acting on a `defun' for FUNCTION, and the function was
instrumented, `Edebug: FUNCTION' is printed in the minibuffer. If not
instrumented, just FUNCTION is printed.
If not acting on a `defun', the result of evaluation is displayed in
the minibuffer. This display is controlled by the variables `eval-expression-print-length' and `eval-expression-print-level', which see.