{{< Concepts >}}

Extract Variable

Extract an expression to be stored into a write-once variable, then read once.

Constraints

Introducing a variable can change the order of operations. Here are some examples to watch out for:

Conditional operators (||, &&) short-circuit. Either extract the whole expression, or extract as a lambda.
Function calls (including overloaded operators) have side effects. Extract as a lambda.
Increment/decrement operations (i++) for variables that are used elsewhere in the statement. Only extract if you can take (or leave behind) every reference to that variable from the statement.

Recipe

If there are side effects in the expression you want to extract, extract a lambda instead (See Extract Function (fix link)).

Otherwise:

Select the expression you want to extract.
CUT
Type applesauce
On the line above, type auto applesauce = and PASTE and type ;

NOTE: If the extracted expression yields a reference, and the lifetime of the referenced object is managed by something else, then you should type auto& instead of auto.