FsCombinators 0.11.5

Purpose

The modules in this project facilitate the use of common patterns in functional programming in the F# programming language. The modules are detailed below. Implementations are short and often naive; refer to the documentation and/or source of each module for further details.

Core

From sources such as SKI combinatory logic, the B,C,K,W system and Raymond Smullyan's "To Mock a Mockingbird". In this module, Smullyan's naming is mostly used, as those names are easy to search for.

BooleanExtensions

Feel free to suggest important boolean combinators that would be widely used and not yet available elsewhere. Generally I find it difficult to name such combinators well enough to improve readability rather than hinder understanding.

Exckit (Exceptions Kit)

This is an attempt to make it easier to deal with libraries that throw lots of Exceptions, especially in cases that could be argued to be non-exceptional. It uses a categorisation proposed here: https://ericlippert.com/2008/09/10/vexing-exceptions/.

ExtraTypes

This offers an alternative ternary form of the Result type, named IgnorableResult. The practical basis for this type is scenarios in which there may be a failure, but the failure is not considered a problem. Some potential uses for the Ignore case:

• a warning might be issued;
• there might just be no effect in a case where an effect was intended but not necessary.

This module also provides a mechanism to group a collection of IgnorableResult values, as described in groupResultGeneric (which has a reference implementation for the Seq type).

OptionExtensions

This was an early pre-cursor to the more generally useful Exckit module. It makes a lazy assumption about the nature of exceptions.

ResultExtensions

Similar to OptionExtensions, but with a domain of type Result.

SeqExtensions

It's common to need to apply some predicate over a Seq of elements, or a Seq of predicates over some value, or even both together. This module provides some tools to do that without rewriting the same logic all over the place. It also provides a pre-order traversal of a graph, with certain assumptions.

StringExtensions

While the F# String type does provide a range of idiomatic functions for working with text, there's plenty left to rewrite frequently using the underlying types. This module does its bit to narrow that gap - it's still wide!

Tuple2

There's potential for more specialisation here, but there are existing libraries that take this seriously and offer a comprehensive feature set. Rather than reproduce all that, this just does what I needed for my purposes.