A markdown to html converter with sequence diagram and flowchart support. Generating documents including diagrams has advantages:

• Docs can be checked into version control like source code, and can compare changes effectively as it is all text
• Making and updating diagrams using drawing software is slow

It converts markdown codeblocks for diagrams using Graphviz and plotutils. Pseudocode to Graphviz is inspired by this gist. Pseudocode is converted to dot file and then Graphviz's dot program converts it to vector image. Sequence diagram uses sequence.pic macros from umlgraph to convert sequence diagram code to plotutls' pic format. Plotutils' pic2plot program generates vector image from the pic.

• Ruby 1.9.2 and up
• Graphviz (tested with dot version 2.38.0)
• Plotutils (tested with pic2plot 2.6)

$ brew install graphviz plotutils

$ apt-get install graphviz plotutils

$ gem install markdoc

For bundler add gem markdoc to your Gemfile.

$ markdoc document.md > document.html

Generated html includes inline svg diagrams, eliminating need for attached image files. It provides 3 executables:

• markdoc converts markdown document to html
• pseudo2svg converts pseudocode to svg image (see below for pseudocode format)
• sequence2svg converts sequence diagram spec to svg image(see below for sequence diagram spec format)

Currently it supports only if/else branch logic, but you can achieve a lot with it.

if ConditionN
  Action-A
  Action-B
else
  Action-C
end

Include codeblock with pseudo language in your markdown.

```pseudo
visit registration page
enter email address
if new user
  fill in registration form
  submit
  if validation error
    fix registration form
    review the fix
    submit
  else
    submit
  end
else
  enter password
  if password wrong
    ask password again
  else
    good to go
  end
  confirm account info
end
confirm registration info
```

Or you could compile individual pseudocode to vector image. Below is generated by:

$ pseudo2svg examples/example.pseudo > examples/flowchart.svg

Include codeblock with sequence language in your markdown. Sequence diagram starts with actor declaration(becomes symbol of man), then object declaration(becomes big rectangles with vertical lifeline), then follows messages. Message format is:

• A -> B : Label - Arrow from A to B with Label over it. Arrows work either way, so it is equivalent to B <- A : Label
• A <~ B : Label - Dashed arrow representing return message. Also works for other direction. so it is same as B ~> A : Label
• C : Label - Message to C itself. Actually it is same as C -> C : Label

```sequence
Student = Actor
P = Partner Site
App = Web App
Api = Reg API

Student -> P : Choose course(S)
P -> Api : Issue key for(S)
P <~ Api : Registration key(K)
P -> App : Register with key(K)
Student <~ App : Registration form
Student -> App : Fill the form(F)
App : Save the form(F)
App -> Api : Register(K, F) # New API
Api : Create course
App <~ Api : Course details(C)
App : Save(C)
Student <~ App : Show course summary
Student -> Api : Click study button
Student <~ Api : Show mypage
```

Or you could compile individual sequence diagram to vector image. Below is generated by:

$ sequence2svg examples/example.sequence > examples/sequence.svg

When printing docs you might want to break pages at specific line. You can use this markup for that:

<p class="page-break"><!-- break --></p>

See examples/doc.md for complete example.

Fork the repo, and send a pull request. I promise I will merge almost all PR's as soon as you don't break existing behaviour. ;) More than welcome if you implement other diagram types. Please add a bit of test for your implementation if you add a feature.

The MIT License (MIT)

Copyright (c) Lkhagva Ochirkhuyag, 2015

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.