balance ?-w win?
Select the smallest set of parentheses, braces, or brackets that encloses the current cursor position, i.e. pairs (), {}, and [] (but not <>). Starting from the initial position, the command searches backward until it finds one of the opening enclosers: (, {, or [. It ignores any of these characters which is preceded by a backslash. When (if) it finds one then it looks in the other direction for the matching character, again ignoring escaped characters. An error is thrown if any of this fails, and the cursor is returned to the initial position.