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Author: sharpchen

docs/document/Lua/docs/Control Flow.md

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+# Control Flow
+
+## Ternary Operator
+
+**`and .. or` statement can be a replacement of ternary operator, but the trap here is, the expression after `and` must not ever return a falsy value.**
+That is because the statment is not terminated when `cond` was met, it falls to expression after `or`.
+
+```lua
+-- first eval cannot be nil
+local fn  = function()
+    if cond then
+        return true
+    end
+    return nil
+end
+
+_ = cond and fn() or canbe_nil -- canbe_nil might be picked when fn() returns falsy value which is unexpected
+```