<cat>Dev.Intro</cat> <title>From Lua to C#</title> # What is this guide This is meant to give an idea of the major differences between Lua and C#. # Comments ```lua -- Lua comments start with two minus signs --[[ Lua multiline comment example --]] ``` ```csharp // csharp comments start with two slashes, like most other languages /* csharp multiline comment example */ ``` # Global Variables ```lua -- you can define globals anywhere globalVar = 100 ``` ```csharp public class MyClass { // globals need to be in a class public static int GlobalVar = 100; } ``` # Variable Types ```lua -- variables in Lua don't have a static type and can store any data local a = 100 a = "Hello" a = function() print( "Hi" ) end ``` ```csharp var a = 100; // translated as "int a = 100;" because 100 is an int a = "Hello"; // error: can't assign a string to an int ``` # Type conversion ```lua local a = 123 local b = tostring(a) -- "123" local c = tonumber(a) -- 123 ``` ```csharp var a = 123; var b = a.ToString(); // "123" var c = int.Parse(b); // 123, will throw an exception if 'b' isn't int-ish // operator 'as' converts an object reference or returns 'null' on failure var vehicle = new Car() as Vehicle; // downcast Car reference to Vehicle var vehicle = vehicle as Car; // upcast Vehicle reference to Car ``` # Numbers ```lua local a = 100 a = 5.5 a = -300.1 ``` ```csharp // integer types are sbyte, byte, short, ushort, int, uint, long, ulong⤶ int a = -300; uint b = 333333; ⤶ // decimal types are float, double, decimal⤶ double d = -500.888; ```⤶ ⤶ # Strings⤶ ⤶ ```lua⤶ local str = "Hello"⤶ local str2 = 'Hello2'⤶ local multilineStr = [[⤶ Hello⤶ Multiline⤶ ]]⤶ ⤶ print(#str) -- 5, string length⤶ ⤶ local concated = "I have " .. 3 .. " apples!"⤶ local formatted = string.format("I have %d apples!", 3)⤶ ```⤶ ⤶ ```csharp⤶ var str = "Hello";⤶ var singleChar = 'a'; // single quotes are for a single character, not a string⤶ var multilineStr = @"⤶ Hello⤶ Multiline⤶ "; // putting '@' before a string literal makes it a verbatim string literal⤶ ⤶ Console.WriteLine(str.Length); // 5, string length⤶ ⤶ var concated = "I have " + 3 + " apples!";⤶ ⤶ // {0} and {1} here correspond to the order of value arguments⤶ // argument number 0 is '3' and argument number 1 is '2'⤶ var formatted = string.Format("I have {0} apples and {1} oranges!", 3, 2);⤶ ⤶ // putting '$' before a string allows interpolating values into it using '{value}'⤶ var interploated = $"I have {3} apples!"; ⤶ ``` # Collections ```lua local stuff = { 1, 2, 3, "Oh", "Hi", "Mark", { myFunc = function() end } } ``` ```csharp var numbers = new int[3] { 1, 2, 3 }; var strings = new List<string> { "Oh", "Hi", "Mark" }; var functions = new Dictionary<string, Action> { ["myFunc"] = () => { } }; ``` # Member Access In Lua anything is accessible from anywhere as long as you have a reference. ```lua -- myFile.lua myTable = { field = 100 } ``` ```lua -- otherFile.lua print( myTable.field ) -- 100 ``` In C# things can be **public**, **private**, **protected** and **internal**. ```csharp // MyClass.cs public class MyClass { public static void PublicMethod() { ... } protected static void ProtectedMethod() { ... } private static void PrivateMethod() { ... } } ``` ```csharp // OtherClass.cs public class OtherClass : MyClass { public static void Test() { MyClass.PublicMethod(); // OK MyClass.ProtectedMethod(); // we inherit from MyClass so OK MyClass.PrivateMethod(); // error: PrivateMethod is private } } ```