Modern C++: Efficient and Scalable Application Development

How it works...

The first thing you need to consider when writing a recursive lambda is that a lambda expression is a function object and, in order to call it recursively from the lambda's body, the lambda must capture its closure (that is, the instantiation of the lambda). In other words, the lambda must capture itself and this has several implications:

• First of all, the lambda must have a name; an unnamed lambda cannot be captured in order to be called again.
• Secondly, the lambda can only be defined in a function scope. The reason for this is that a lambda can only capture variables from a function scope; it cannot capture any variable that has a static storage duration. Objects defined in a namespace scope or with the static or external ...