Added monarch.is_popup() (#70)

monarch/monarch.lua

@@ -188,6 +188,17 @@ function M.is_visible(id)
 end
 
 
+--- Check if a screen is a popup
+-- @param id Screen id
+-- @return true if the screen is a popup
+function M.is_popup(id)
+	assert(id, "You must provide a screen id")
+	id = tohash(id)
+	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
+	return screens[id].popup
+end
+
+
 local function register(id, settings)
 	assert(id, "You must provide a screen id")
 	id = tohash(id)

test/test_monarch.lua

@@ -572,5 +572,11 @@ return function()
 			local ok, err = monarch.post(POPUP1, "foobar")
 			assert(not ok and err, "Expected monarch.post() to return false plus an error message")
 		end)
+
+
+		it("should be able to check if a screen is is a popup", function()
+			assert(not monarch.is_popup(SCREEN1))
+			assert(monarch.is_popup(POPUP1))
+		end)
 	end)
 end