> # it is conventional to prefix the variable variable with

> # a string literal so that it's easy to search for where the

> # variable variable is being used.

> local key = $(.my-expensive-rule-cache-$(targets)) ;

 

I made a mistake in the above example:

 

The line:

local key = $(.my-expensive-rule-cache-$(targets)) ;

 

Should be:

local key = .my-expensive-rule-cache-$(targets) ;