Emacs has a number of parenthesis matching features, which make it easy to see how and whether parentheses (or other delimiters) match up.
Whenever you type a self-inserting character that is a closing delimiter, Emacs briefly indicates the location of the matching opening delimiter, provided that is on the screen. If it is not on the screen, Emacs displays some of the text near it in the echo area. Either way, you can tell which grouping you are closing off. If the opening delimiter and closing delimiter are mismatched—such as in ‘[x)’—a warning message is displayed in the echo area.
Three variables control the display of matching parentheses:
nildisables it, but the default is t to enable it. Set it to
jumpto make indication work by momentarily moving the cursor to the matching opening delimiter. Set it to
jump-offscreento make the cursor jump, even if the opening delimiter is off screen.
Show Paren mode, a global minor mode, provides a more powerful kind of automatic matching. Whenever point is before an opening delimiter or after a closing delimiter, the delimiter, its matching delimiter, and optionally the text between them are highlighted. To toggle Show Paren mode, type M-x show-paren-mode. To customize it, type M-x customize-group RET paren-showing. The customizable options which control the operation of this mode include:
show-paren-highlight-open-parencontrols whether to highlight an open paren when point stands just before it, and hence its position is marked by the cursor anyway. The default is non-
parenthesis(show the matching paren),
expression(highlight the entire expression enclosed by the parens), and
mixed(highlight the matching paren if it is visible, the expression otherwise).
nil, causes highlighting also when point is on the inside of a parenthesis.
nil, causes highlighting also when point is in whitespace at the beginning or end of a line, and there is a paren at, respectively, the first or last, or the last, non-whitespace position on the line.
Electric Pair mode, a global minor mode, provides a way to easily insert matching delimiters. Whenever you insert an opening delimiter, the matching closing delimiter is automatically inserted as well, leaving point between the two. Conversely, when you insert a closing delimiter over an existing one, no inserting takes places and that position is simply skipped over. These variables control additional features of Electric Pair mode:
electric-pair-preserve-balance, when non-
nil, makes the default pairing logic balance out the number of opening and closing delimiters.
electric-pair-delete-adjacent-pairs, when non-
nil, makes backspacing between two adjacent delimiters also automatically delete the closing delimiter.
electric-pair-open-newline-between-pairs, when non-
nil, makes inserting inserting a newline between two adjacent pairs also automatically open and extra newline after point.
electric-pair-skip-whitespace, when non-
nil, causes the minor mode to skip whitespace forward before deciding whether to skip over the closing delimiter.
To toggle Electric Pair mode, type M-x electric-pair-mode. To toggle the mode in a single buffer, use M-x electric-pair-local-mode.