13.1 Groups and blocks: delimiter highlighting

Delimiters for groups (<< and >>) and blocks (begin and end) are treated like brackets. Either highlighting of matching group and block delimiters or (group only) blink matching is toggled by the command reduce-show-delim-mode.

REDUCE Show Delim mode is based closely on Show Paren mode; Automatic Display Of Matching Parentheses in The Emacs Editor. It is completely independent except that all settings default to the corresponding values for Show Paren mode. Show Delim mode applies to both REDUCE mode and REDUCE Run mode (Running REDUCE in an Emacs window) and is turned on automatically when a REDUCE mode is selected if reduce-show-delim-mode-on is non-nil, which it is by default if Show Paren mode is on.

Note that highlighting of matching group and block delimiters does not work when point is within a delimiter. (This cannot happen with brackets, which are single characters). This may be changed in future.

M-x reduce-show-delim-mode

Toggle REDUCE Show Delim mode. With a prefix argument, turn the mode on if and only if the argument is positive. REDUCE Show Delim mode highlights matching group or block delimiters after show-paren-delay seconds of Emacs idle time.

Show Delim mode is a buffer-local minor mode. 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 customize REDUCE Show Delim mode, type M-x customize-group RET reduce-delim-showing. The customizable options which control the operation of this mode include the following: