Domain Modeling Made Functional

Making Life Easier with Computation Expressions

So far we’ve been dealing with straightforward error-handling logic. We’ve been able to chain together Result-generating functions using bind; and for those functions that were not two-track, we’ve been able to make them fit the two-track model using various “adapter” functions.

Sometimes, though, the workflow logic is more complicated. You may need to work within conditional branches, or loops, or work with deeply nested Result-generating functions. In cases like these, F# offers some relief in the form of “computation expressions.” A computation expression is a special kind of expression block that hides the messiness of bind behind the scenes.

It’s easy to create your own computation expressions. ...