MIME rendering

[SpencerPark]

Initial support for rendering richer displays of data in the notebook. The approach was designed to follow IPython's API as far as it applies in Go. Any code that needs access to the kernel should be injected right before evaluation but generic user space stuff should go in the runtime package.

An example I've been playing around with is below. There is still a bug I can't quite track down yet with the zmq message being somehow corrupted during Publish and so in random cases the results may or may not show up due to the message being rejected (which means if it doesn't work try it a second time until this is fixed). (Fixed in 710233f)

import "fmt"
import r "github.com/gopherdata/gophernotes/runtime"

type Test struct {
    Color string
}

func (t Test) RenderAsSVG() string {
    return "<svg><rect x=\"0\" y=\"0\" width=\"100\" height=\"100\" fill=\"" + t.Color + "\"/></svg>"
}

func (t Test) RenderAsMarkdown() string {
    return "**Color:** " + t.Color
}

t := Test{"blue"}

fmt.Println(t)
Display(r.SVG(t))
Display(r.Markdown(t))

Still TODO:

• Add some unit tests
• Add example notebooks
• Implement some renderers for standard library interfaces

[SpencerPark]

Ran into trouble with cosmos72/gomacro#16. A lot of the rendering logic requires type assertions and unfortunately many of those are interfaces.

[cosmos72]

If you don't mind, I tried to simplify your code, see issue #17 and pull request #105

[SpencerPark]

If you don't mind, I tried to simplify your code

Not at all! You know gomacro's capabilities much better than I do :) I'll move the discussion over there.

[cosmos72]

as per discussion in #105, I merged that pull request