@@ -5,27 +5,8 @@
 	['render:format'] = 'html';
 	['html:gen-styles'] = true;
 }
 
-local function
-kmap(fn, list)
-	local new = {}
-	for k, v in pairs(list) do
-		local nk,nv = fn(k,v)
-		new[nk or k] = nv or v
-	end
-	return new
-end
-
-local function
-kfilter(list, fn)
-	local new = {}
-	for k, v in pairs(list) do
-		if fn(k,v) then new[k] = v end
-	end
-	return new
-end
-
 local function
 main(input, output, log, mode, suggestions, vars)
 	local doc = ct.parse(input.stream, input.src, mode)
 	input.stream:close()
@@ -46,11 +27,11 @@
 	if not ct.render[mode['render:format']] then
 		ct.exns.unimpl('output format “%s” unsupported', mode['render:format']):throw()
 	end
 	
-	local render_opts = kmap(function(k,v)
+	local render_opts = ss.kmap(function(k,v)
 		return k:sub(2+#mode['render:format'])
-	end, kfilter(mode, function(m)
+	end, ss.kfilter(mode, function(m)
 		return ss.str.begins(m, mode['render:format']..':')
 	end))
 
 	doc.vars = vars
@@ -139,8 +120,31 @@
 
 		['mode-weak'] = function(key,value) suggestions[checkmodekey(key)] = value end;
 		['mode-set-weak'] = function(key) suggestions[checkmodekey(key)] = true end;
 		['mode-clear-weak'] = function(key) suggestions[checkmodekey(key)] = false end;
+
+		['version'] = function()
+			outp:write(ct.info:about())
+			if next(ct.ext.loaded) then
+				outp:write('\nactive extensions:\n')
+				for k,v in pairs(ct.ext.loaded) do
+					outp:write(string.format(' * %s', v.id ..
+						(v.version and (' ' .. v.version:string()) or '')))
+					if v.desc then
+						outp:write(string.format(': %s', v.desc))
+						if v.contributors then
+							outp:write(string.format(' [%s]', table.concat(
+								ss.map(function(ctr)
+									return ctr.name or ctr.handle
+								end, v.contributors), ', ')))
+						end
+					else
+						outp:write'\n'
+					end
+				end
+			end
+			os.exit(0)
+		end
 	}
 
 	local args = {}
 	local keepParsing = true
@@ -152,17 +156,19 @@
 			local nargs = optnparams(longopt)
 
 			if nargs > 1 then
 				if i + nargs > #arg then
-					ct.exns.cli('not enough arguments for switch --%s (%u expected)', longopt, nargs):throw()
+					ct.exns.cli('not enough arguments for switch --%s (%s expected)', longopt, nargs):throw()
 				end
 				local nt = {}
 				for j = i+1, i+nargs do
 					table.insert(nt, arg[j])
 				end
-				onswitch[longopt](table.unpack(nt))
+				print('onsw')
 			elseif nargs == 1 then
 				onswitch[longopt](arg[i+1])
+			else
+				onswitch[longopt]()
 			end
 			i = i + nargs
 		end
 		if v == '--' then
@@ -176,9 +182,9 @@
 					for c,p in ss.str.enc.utf8.each(v:sub(2)) do
 						if optmap[c] then
 							execLongOpt(optmap[c])
 						else
-							ct.exns.cli('switch -%i unrecognized', c):throw()
+							ct.exns.cli('switch -%s unrecognized', c):throw()
 						end
 					end
 				else
 					table.insert(args, v)