<function name="Either" parent="Global" type="libraryfunc"> <description>An [eagerly evaluated](https://en.wikipedia.org/wiki/Eager_evaluation) [ternary operator](https://en.wikipedia.org/wiki/%3F:), or, in layman's terms, a compact "if then else" statement. In most cases, you should just use Lua's ["pseudo" ternary operator](https://en.wikipedia.org/wiki/%3F:#Lua), like this: ``` local myCondition = true local consequent = "myCondition is true" local alternative = "myCondition is false" print(myCondition and consequent or alternative) ``` ⤶ However, in very rare cases, you may find `Either` useful. In the above example, due to [short-circuit evaluation](https://en.wikipedia.org/wiki/Short-circuit_evaluation), `consequent` would be "skipped" and ignored (not evaluated) by Lua due to `myCondition` being `true`, and only `alternative` would be evaluated. However, when using `Either`, both `consequent` and `alternative` would be evaluated. A practical example of this can be found below.⤶ ⤶ If `consequent` is "falsey" (Lua considers both `false` and `nil` as false), this will not work. For example:⤶ ⤶ ```⤶ local X = true⤶ local Y = false⤶ local Z = "myCondition is false"⤶ ⤶ print(X and Y or Z)⤶ ```⤶ ⤶ This will actually print the value of `Z`.⤶ ⤶ In the above case, and other very rare cases, you may find `Either` useful. In the above example, due to [short-circuit evaluation](https://en.wikipedia.org/wiki/Short-circuit_evaluation), `consequent` would be "skipped" and ignored (not evaluated) by Lua due to `myCondition` being `true`, and only `alternative` would be evaluated. However, when using `Either`, both `consequent` and `alternative` would be evaluated. A practical example of this can be found below.⤶ </description> <realm>Shared and Menu</realm> <file line="362-L365">lua/includes/util.lua</file> <args> <arg name="condition" type="any">The condition to check if true or false.</arg> <arg name="truevar" type="any">If the condition isn't nil/false, returns this value.</arg> <arg name="falsevar" type="any">If the condition is nil/false, returns this value.</arg> </args> <rets> <ret name="" type="any">The result.</ret> </rets> </function> <example> <description>The following two `print` statements have identical results.</description> <code> local ply = Entity( 1 ) print( "Player " .. Either( ply:IsAdmin(), "is", "is not" ) .. " an admin" ) print( "Player " .. ( ply:IsAdmin() and "is" or "is not" ) .. " an admin" ) </code> <output>If Player 1 is admin, it will print "Player is an admin".</output> </example> <example> <description>A practical example of the behavior of this function in comparison to Lua's ["pseudo" ternary operator](https://en.wikipedia.org/wiki/%3F:#Lua), demonstrating [short-circuit evaluation](https://en.wikipedia.org/wiki/Short-circuit_evaluation), and the lack of it when using `Either`.</description> <code> local function printHello() print( "Hello, world!" ) return "printHello called" end local myCondition = true print( myCondition and "printHello not called" or printHello() ) print( Either( myCondition, "myCondition is true, but printHello was still called", printHello() ) ) </code> <output> ``` printHello not called Hello, world! myCondition is true, but printHello was still called ``` </output> </example>