add calculator widget

community/calc-widget.lua

@@ -0,0 +1,62 @@
+-- name = "Калькулятор"
+-- description = "Работает с математическими, строковыми и логическими операторами и функциями"
+-- type = "widget"
+-- author = "Andrey Gavrilov"
+-- version = "1.0"
+
+local maths = {"abs", "acos", "asin", "atan", "ceil", "cos", "cos", "deg", "exp", "floor", "fmod", "frexp", "huge", "ldexp", "log", "max", "min", "modf", "pi", "pow", "rad", "random", "sin", "sqrt", "tan"}
+local strings = {"byte", "char", "dump", "find", "format", "len", "lower", "match", "rep", "reverse", "sub", "upper"}
+local types = {"nil", "function", "table", "userdata", "thread"}
+
+function on_alarm()
+    ui:show_text("Введите выражение")
+end
+
+function on_click()
+    ui:show_edit_dialog("Введите выражение")
+end
+
+function on_dialog_action(text)
+    if text == "" then
+        on_alarm()
+    else
+        ui:show_text("Результат: "..calculate_string(text))
+    end
+end
+
+function calculate_string(text)
+    local str = format_str(text)
+    local f = load("return "..str)
+    local status, result = pcall(f)
+    if get_index(types, type(result)) > 0 or not status then
+        result = "неопределён"
+    else
+        result = tostring(result)
+        system:copy_to_clipboard(result)
+    end
+    return result
+end 
+ 
+function format_str(text)
+    text = text:gsub("pi", "math.pi")
+    text = text:gsub("π", "math.pi")
+    text = text:gsub("math%.math", "math")
+    local pattern = "(√) ?(%d+%.?%d*)"
+    local oper, first = text:match(pattern)
+    if oper == "√" then
+        return "math.sqrt("..first..")"
+    end
+    local pattern = "(%d+%.?%d*) ?([+-*/%^]) ?(%d+%.?%d*)"
+    local first, oper, last = text:match(pattern)
+    if oper == "^" then 
+         return "math.pow("..first..", "..last..")"
+    end
+    func = text:match("^%a+")
+    if get_index(maths, func) > 0 then
+        return "math."..text
+    end
+    if get_index(strings, func) > 0 then
+        return "string.".. text
+    end
+    return text
+end