add samples

samples/chart-sample2.lua

@@ -0,0 +1,39 @@
+local api_url = "https://api.covid19api.com/country/ru?from=2021-07-01T00:00:00Z&to=2021-07-31T00:00:00Z"
+
+local tab = {}
+
+function on_alarm()
+    http:get(api_url)
+end
+
+function on_network_result(result)
+    tab = get_tab_ajson(result)
+    ui:show_chart("Covid", tab, "x:date y:number")
+end
+
+function totime(str)
+    local y,m,d = str:match("(%d+)-(%d+)-(%d+)")
+    return os.time{year=y, month=m, day=d}*1000
+end
+
+function get_tab_ajson(result)
+    local tab = {}
+    local dat = ajson:get_value(result, "array object:0 string:Date")
+    local conf = ajson:get_value(result, "array object:0 int:Confirmed")
+    local prev_conf = conf
+    local new = conf - prev_conf
+    tab[1] = {totime(dat), new}
+    local i = 1
+    while true do
+        dat = ajson:get_value(result, "array object:"..i.." string:Date")
+        if dat:match("Error") == "Error" then
+            break
+        end
+        conf = ajson:get_value(result, "array object:"..i.." int:Confirmed")
+        new = conf - prev_conf
+        prev_conf = conf
+        tab[i] = {totime(dat), new}
+        i = i+1
+    end
+    return tab
+end