14.1 Functional programming and concurrency
The most effective concurrent processing occurs when there are no dependencies among the tasks being performed. The biggest difficulty in developing concurrent (or parallel) programming is the complications arising from coordinating updates to shared resources, where tasks depend on a common resource.
When following functional design patterns, we tend to avoid stateful programs. A functional design should minimize or eliminate concurrent updates to shared objects. If we can design software where lazy, non-strict evaluation is central, we can also design software where concurrent evaluation is helpful. In some cases, parts of an application can have an embarrassingly parallel design, where most of the work can be done concurrently with few or no interactions among computations. Mappings and filterings, in particular, benefit from parallel processing; reductions typically can’t be done in parallel.
The frameworks we’ll focus on...
