For the past two weeks or so I've been grappling with trying to build a simple HTTP front-end for my ruby Tic-Tac-Toe program. There have been some non-technical hurdles with scheduling and other projects demanding my time, but I've also spent a fair amount of time simply struggling to put the pieces together with how the Rack libraries work.
Rack as a concept is exceptionally simple. Inspired by PEP 333 which specified the Python Web Server Gateway Interface or WSGI, Rack has come to be the de-facto way that Ruby applications interface with web servers. Beyond the basic concept, Rack provides a set of helper libraries. These include many useful middleware and convenience classes for things like static file serving, sessions, and request parsing and response generation. However, the documentation for the classes included in Rack is pretty dismal.
For the most part it is all auto-generated documentation, but many of the classes have only a vague description of what they do, with no indication of how they're meant to be used. Conspicuously absent or good examples of configuration of middleware, especially in the special DSL that is made available in rackup files.
Given the number of different web frameworks that are built on top of Rack, it's sort of shocking to me that the documentation is in this sort of state. Though I guess it's consistent with my general experience of Ruby libraries as a whole.
I've really worked in Ruby since I started my apprenticeship at 8th Light, but from what I've seen, many Ruby libraries have awkward gaps in their documentation. For instance, Guard is an amazing and vital piece of a smooth Ruby TDD toolchain. But it's documentation is incredibly cryptic about how to properly setup a Guardfile. There are more paragraphs about how to debug problems in your Guardfile than what the format is!
Now documentation is hard. But over the last several years, it's been increasingly clear to me that good documentation is one of the most valuable assets that a software product can have, especially an open-source one.
So then why is writing good documentation still so elusively difficult? I know I struggle with it immensely. The majority of my projects have little to no documentation, with the notable exception of Hermit.
I think there are a few reasons. First off, writing in general is hard. It takes effort, and the will to keep re-writing and trying new things to end up with a nicely polished piece of writing that reads well, and communicates the author's intent clearly and succinctly.
Another reason is that it's much easier to polish a piece of writing with good critical feedback from someone else. The complicating factor for code documentation is that you need to find the right audience to give you feedback. Often this means someone who is totally unfamiliar with your exact software, but if it's code documentation it probably also can't be your friend who only uses their computer for writing Word documents and checking their social media.
But I think the final reason is that we don't do it enough. Again, like all other writing, the best way to get better at it, is simply by writing lots and lots of documentation. Also, critically reading the documentation that you read, and reflecting on what is helpful, and what isn't.