I've been thinking about a calculator/scratch pad for a while, and I've just realised that what I actually want is the Smalltalk environment.

Imagine a blank screen. Click anywhere and start typing. Select text, right click and 'evaluate'. Right click to bring up tools (number pad, calendar, file upload whynot, timers, API calls). I also want to be able to link bits together, so the output of one calculation can feed into another.

It's persistant (changes are saved straight away) and maybe networked (so that I can open the page here or on my phone or at work).

Its got bits of OneNote, but that doesn't have any calculation/scripting.

I'm also thinking about 'layers' rather than 'pages' - layers stack on top of each other, and can be turned off and on. Disabled layers don't contribute to calculations.

Adding in data pipelines, to take e.g. a JSON source, parse it, filter it, reduce it, give an output, or a base64 encoded blob, decode it to utf8.