Trenni::Markdown

Trenni::Markdown is a deliberately light-weight and simple Markdown parser. It doesn't cover the entire spec but only a small subset required for implementing literate unit tests, which are markdown documents which include unit tests.

I've been writing a bit of C++ code lately and been thinking about how to document it in a way that is actually practically useful. Initially I started working on ffi-clang to extract comments and symbols from C++ code. But, I found this ultimately produced unsatisfying output.

I discussed this with a friend and reviewed what I thought was good documentation. I found I tended to prefer short tangible examples, high-level use-cases that demonstrate the functionality of the library in a practical sense. He mentioned literate programming.

I started thinking about what would be the ideal documentation. In most cases, I end up copying examples from the unit tests into the main README. This is a bit tedious but I feel it gives a good high level summary of how and why you would use a library.

I stated thinking, rather than extracting the code, what about if the README could BE code. What about if the unit tests were actual markdown which could be compiled, and used to document the code in a very tangible way?

The name of this gem is a bit misleading but essentially what it does is generate code from an input markdown document according to some generator implemented in Ruby. The idea is that you could write unit tests (there is an included proof of concept for RSpec) as a readable markdown document. This would serve as the basis for the documentation and tie into the automatically generated documentation which is often hard to get a handle on in large projects. It would be the tangible entry point for high-level functionality, while the underlying symbol/comment index would be the foundation.

bundler add trenni-markdown

• foo
• bar

A command line binary is included for basic transforms (using examples/test.md in this example):

$ trenni-markdown generate -g RSpec examples/test.md
RSpec.describe String.new("Test") do
	
	# This test checks that strings report the inclusion of letters correctly.
	
	it "should contain the letter e" do
		expect(subject).to include('e')
	end
	
	it "shoudn't contain the letter m" do
		expect(subject).to_not include('m')
	end
end

The command line is essentially implemented as follows:

buffer = Trenni::FileBuffer.new(path)
generator = Trenni::Markdown::Generators::RSpec.new

Trenni::Markdown::Parser.new(buffer, generator).parse!

puts generator.output

If you just want to parse the subset of markdown supported by Trenni::Markdown, you can do so:

input = "# Title\nParagraph\n"
buffer = Trenni::Buffer.new(input)
Trenni::Markdown::Parser.new(buffer, delegate).parse!

The delegate must respond to the following callbacks:

@delegate.heading(level, text)
@delegate.paragraph(text)
@delegate.code(lines)

Keep in mind that this is not a general purpose markdown parser, but specifically for the generation of literate code.

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

Released under the MIT license.

Copyright, 2012, 2016, by Samuel G. D. Williams.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.