Defines a pattern to be highlighted in the current window (a "match"). It will be highlighted with {group}. Returns an identification number (ID), which can be used to delete the match using |matchdelete()|. The ID is bound to the window. Matching is case sensitive and magic, unless case sensitivity or magicness are explicitly overridden in {pattern}. The 'magic', 'smartcase' and 'ignorecase' options are not used. The "Conceal" value is special, it causes the match to be concealed. The optional {priority} argument assigns a priority to the match. A match with a high priority will have its highlighting overrule that of a match with a lower priority. A priority is specified as an integer (negative numbers are no exception). If the {priority} argument is not specified, the default priority is 10. The priority of 'hlsearch' is zero, hence all matches with a priority greater than zero will overrule it. Syntax highlighting (see 'syntax') is a separate mechanism, and regardless of the chosen priority a match will always overrule syntax highlighting. The optional {id} argument allows the request for a specific match ID. If a specified ID is already taken, an error message will appear and the match will not be added. An ID is specified as a positive integer (zero excluded). IDs 1, 2 and 3 are reserved for |:match|, |:2match| and |:3match|, respectively. If the {id} argument is not specified or -1, |matchadd()| automatically chooses a free ID. The optional {dict} argument allows for further custom values. Currently this is used to specify a match specific conceal character that will be shown for |hl-Conceal| highlighted matches. The dict can have the following members: conceal Special character to show instead of the match (only for |hl-Conceal| highlighted matches, see |:syn-cchar|) window Instead of the current window use the window with this number or window ID. The number of matches is not limited, as it is the case with the |:match| commands. Example: :highlight MyGroup ctermbg=green guibg=green :let m = matchadd("MyGroup", "TODO") Deletion of the pattern: :call matchdelete(m) A list of matches defined by |matchadd()| and |:match| are available from |getmatches()|. All matches can be deleted in one operation by |clearmatches()|. Can also be used as a |method|: GetGroup()->matchadd('TODO')