C.lambdas

C.lambdas: Function objects and lambdas

A function object is an object supplying an overloaded () so that you can call it. A lambda expression (colloquially often shortened to "a lambda") is a notation for generating a function object. Function objects should be cheap to copy (and therefore passed by value).

Summary:

• F.10: If an operation can be reused, give it a name
• F.11: Use an unnamed lambda if you need a simple function object in one place only
• F.50: Use a lambda when a function won't do (to capture local variables, or to write a local function)
• F.52: Prefer capturing by reference in lambdas that will be used locally, including passed to algorithms
• F.53: Avoid capturing by reference in lambdas that will be used non-locally, including returned, stored on the heap, or passed to another thread
• ES.28: Use lambdas for complex initialization, especially of const variables