Vim: Unite plugin: 'menu' source: Solution to merge all child elements from all groups to single group

unite-all-menu-source.vim

let s:u_all = []
let s:u_max_prefix_length = 0
for [k, v] in items(g:unite_source_menu_menus)
	if s:u_max_prefix_length < len(v.description)
		let s:u_max_prefix_length = len(v.description)
	endif
	for item in v.command_candidates
		call add(s:u_all, [v.description, item[0], item[1]])
	endfor
endfor
let s:u_all_pfx = []
for item in s:u_all
	let s:u_desc = item[0]
	while len(s:u_desc) < s:u_max_prefix_length
		let s:u_desc = s:u_desc . ' '
	endwhile
	call add(s:u_all_pfx, [s:u_desc . ' | ' . item[1], item[2]])
endfor
let g:unite_source_menu_menus.all = { 'description': 'All actions' }
let g:unite_source_menu_menus.all.command_candidates = s:u_all_pfx
unlet s:u_all
unlet s:u_all_pfx
unlet s:u_max_prefix_length
unlet s:u_desc