inline gnuplot

Time to time I find myself needing to plot histograms and approximations in occasional posts. Similar to inline graphviz support today I added gnuplot svg inlining support into this blog. The trivial example looks this way:

The above is generated using the following .md snippet:

```{render=gnuplot}
plot [-pi:pi] sin(x)
```

hakyll integration is also straightforward:

inlineGnuplot :: TP.Block -> Compiler TP.Block
inlineGnuplot cb@(TP.CodeBlock (id, classes, namevals) contents)
  | ("render", "gnuplot") `elem` namevals
  = TP.RawBlock (TP.Format "html") . DT.pack <$> (
      unixFilter "gnuplot"
          [ "--default-settings"
          , "-e", "set terminal svg"
          , "-"]
          (DT.unpack contents))
inlineGnuplot x = return x

Here we call gnuplot --default-settings -e "set terminal svg" - and pass our script over stdin. Easy! For those who wonder what gnuplot is capable of have a look at gnuplot.info demo page. As a bonus here is the time chart of my commits into nixpkgs:

Have fun!