1Black Friday
 2============
 3
 4This is an implementation of John Gruber's [markdown][1] in [Go][2].
 5It is a translation of the [upskirt][3] library written in C with a
 6few minor changes. It retains the paranoia of the original (it is
 7careful not to trust its input, and as such it should be safe to
 8feed it arbitrary user-supplied inputs). It also retains the
 9emphasis on high performance, and the source is almost as ugly as
10the original.
11
12HTML output is currently supported, along with Smartpants
13extensions.
14
15
16Installation
17------------
18
19Assuming you have recent version of Go installed, along with git:
20
21    goinstall github.com/russross/blackfriday
22
23will download, compile, and install the package into
24`$GOROOT/src/pkg/github.com/russross/blackfriday`.
25
26Check out `example/main.go` for an example of how to use it. Run
27`gomake` in that directory to build a simple command-line markdown
28tool:
29
30    cd $GOROOT/src/pkg/github.com/russross/blackfriday
31    gomake markdown
32
33will build the binary `markdown` in the `example` directory.
34
35
36Features
37--------
38
39All features of upskirt are supported, including:
40
41*   The Markdown v1.0.3 test suite passes with the `--tidy` option.
42    Without `--tidy`, the differences appear to be bugs/dubious
43    features in the original.
44
45*   Common extensions, including table support, fenced code blocks,
46    autolinks, strikethroughs, non-strict emphasis, etc.
47
48*   Paranoid parsing, making it safe to feed untrusted used input
49    without fear of bad things happening. There are still some
50    corner cases that are untested, but it is already more strict
51    than upskirt (Go's bounds-checking uncovered a few off-by-one
52    errors that were present in the C code).
53
54*   Good performance. I have not done rigorous benchmarking, but
55    informal testing suggests it is around 8x slower than upskirt.
56    This is still an ugly, direct translation from the C code, so
57    the difference is unlikely to be related to differences in
58    coding style. There is a lot of bounds checking that is
59    duplicated (by user code for the application and again by code
60    the compiler generates) and there is some additional memory
61    management overhead, since I allocate and garbage collect
62    buffers instead of explicitly managing them as upskirt does.
63
64*   Minimal dependencies. blackfriday only depends on standard
65    library packages in Go. The source code is pretty
66    self-contained, so it is easy to add to any project.
67
68
69Extensions
70----------
71
72In addition to the extensions offered by upskirt, this package
73implements two additional Smartypants options:
74
75*   LaTeX-style dash parsing, where `--` is translated into
76    `–`, and `---` is translated into `—`
77*   Generic fractions, where anything that looks like a fraction
78    is translated into suitable HTML (instead of just a few special
79    cases). For example, `4/5` becomes `<sup>4</sup>&frasl;<sub>5</sub>`
80
81
82Todo
83----
84
85*   Code cleanup
86*   Better code documentation
87*   Implement a LaTeX backend
88
89
90   [1]: http://daringfireball.net/projects/markdown/ "Markdown"
91   [2]: http://golang.org/ "Go Language"
92   [3]: http://github.com/tanoku/upskirt "Upskirt"