doc: denote link completion

README.md

@@ -32,15 +32,22 @@ the help files. This will allow you to get more help using `:help denote` or
 similar commands.
 
 ### Usage
-For following links, simply move your cursor to the denote link, and press
+For _following links,_ simply move your cursor to the denote link, and press
 `gf`.
 
-Browsing and searching notes is implemented using the [location
+This package also provides denote _link completion_ using the
+[|'omnifunc'|](https://vimhelp.org/options.txt.html#%27omnifunc%27) option. So,
+the link is completed after pressing `<C-X><C-O>` while typing any prefix of a
+denote link `denote:<identifier>`. Even more so, if this completion is invoked
+after typing `denote:<str>`, then the link is completed for denote entries
+that have `<str>` as part of the title.
+
+_Browsing_ and _searching notes_ is implemented using the [location
 list](https://vimhelp.org/quickfix.txt.html#location-list).
-So, after running any of the following commands, you may navigate your notes
-using, e.g., `:lopen` to open the list, `:lnext` and `:lprev`, to move to the next or
-previous entry (the list does not need to be opened for that), and `:lclose`
-for closing the location list.
+This means that you may navigate your notes using, e.g., `:lopen` to open the
+list, `:lnext` and `:lprev`, to move to the next or previous entry (the list
+does not need to be opened for that), and `:lclose` for closing the location
+list.
 
 #### Commands
 This package defines the following user commands:

after/ftplugin/markdown.vim

@@ -1,3 +1,6 @@
+" Link completion {{{1
+set omnifunc=denote#completion#get
+
 " Go to file command |gf| adjustments {{{1
 " This resolves denote links. The function has access to the variable v:fname,
 " which corresponds to the filename under the cursor.

autoload/denote/completion.vim

@@ -0,0 +1,59 @@
+" Find the column where the completion starts. This must be between 1 and
+" col('.'). Denote links are of this form: `denote:<identifier>`.
+function s:column()
+	" Get the substring from the start of the line until col('.')
+	let l = getline(".")[:col('.')]
+	" Take the shortest prefix of a denote link. This may be any of
+	" \<d$
+	" ..
+	" \<denote:$
+	" \<denote:\f$
+	" \<denote:\f\f$
+	" etc.
+	let res = l->matchstrpos('\<denote:\f*$')
+	if res[1] >= 0
+		return res[1]
+	endif
+	let res = l->matchstrpos('\<d\f*$')
+	if res[1] == -1
+		return -3
+	endif
+	return 'denote:' =~ '^' .. res[0] ? res[1] : -3
+endfunction
+
+" Return completion items given by the base
+function s:suggestions(base)
+	let prefix = a:base->matchstr('^denote:\zs.*$')
+	let flist = glob(prefix ? "*" .. prefix .. "*" : "*", 0, v:true)
+	let res = []
+	for filename in flist
+		let noteId = denote#meta#noteIdFromFile(filename)
+		let noteTitle = denote#meta#noteTitleFromFile(filename)
+		if noteId == v:false || (noteId !~ '^' .. prefix && noteTitle !~ prefix)
+			continue
+		endif
+		let noteTitle = noteTitle ?? '(no title)'
+		let noteTags = denote#meta#noteTagsFromFile(filename)
+		let res = res->add({
+					\ 'word' : 'denote:' .. noteId,
+					\ 'abbr' : noteTitle,
+					\ 'menu' : noteTags->join(', ')
+					\ })
+	endfor
+	return res
+endfunction
+
+function! Myomni(findstart, base)
+	if a:findstart == 1
+		let tmp = s:column()
+		return tmp
+	else
+		let tmp = s:suggestions(a:base)
+		return tmp
+	endif
+endfunction
+
+" Completion function for denote links
+function denote#completion#get(findstart, base)
+	return a:findstart == 1 ? s:column() : s:suggestions(a:base)
+endfunction

autoload/denote/meta.vim

@@ -23,10 +23,9 @@ function denote#meta#noteIdFromFile(filename)
 				\ ?? v:false
 endfunction
 
-" Return the note title from the filename. On failure, v:false is returned.
+" Return the note title from the filename.
 function denote#meta#noteTitleFromFile(filename)
 	return a:filename->matchstr("--\\zs.\\{-\\}\\ze\\(==\\|@@\\|__\\|\\..\\)")->substitute("-", " ", "g")
-				\ ?? v:false
 endfunction
 
 " Return the note tags from the filename as a list.

doc/denote.txt

@@ -21,7 +21,7 @@ do adjusting the tags or changing the title of a note. The official manual is
 available online:
 	https://protesilaos.com/emacs/denote
 
-The denote plugin adds denote-functionality to vim --- the vim way. We are
+The denote plugin adds denote functionality to vim --- _the vim way._ We are
 aware of two other plugins, but we fear that these plugins are not flexible
 enough, and more importantly, do not follow the vim philosophy for handling
 denote notes. These mentioned plugins are available here:
@@ -29,10 +29,13 @@ denote notes. These mentioned plugins are available here:
 	https://git.sr.ht/~ashton314/vim-denote
 
 In contrast to these plugins, the present package relies on the
-|location-list| features for displaying denote entries, and on and
-|'includeexpr'| option for following the links (see, |gf|). This plugin also
-provides custom location-list formatting using the option
-|'quickfixtextfunc'|.
+|location-list| features for displaying denote entries, and on the options
+|'quickfixtextfunc'|, |'includeexpr'|, and |'omnifunc'|. With these, denote
+links can be followed using |gf|, and completed using omni comletion (see,
+|compl-omni|). For link completion, press |i_CTRL-X_CTRL-O| after typing any
+prefix of a denote link. This completion also works with titles: by invoking
+omni completion after typing "denote:foo", denote links are completed for
+entries containing "foo" in the title.
 
 							*denote-commands*
 Commands ~