This is a programmable Gantt chart tool I've been working on. I just released it as a beta to my users today. I'm expecting them to find the formulas very intimidating (although most can use basic excel) but I'll let you know what their feedback is next week! Couldn't fit in the canvassy graphical interface but perhaps another time.

That's really nice! • I like that you show the last computed value above the formula fields. That's a nice bit of UI. • I love that you support units! The main other place I've seen rich unit support like that was in the calculator app Calca, but we should totally have that everywhere. How long have you been working on this? What's the tech stack?

@Ivan Reese thanks! It’s probably taken a year now. The tech stack is all JavaScript. I did an initial version using svg dom elements but it had significant performance issues. So I had to take some time to experiment and learn to code graphics and animations. Now it’s using webgl with three.js and the formulas a parsed using nearley.js . I will be checking out Calca shortly!

http://calca.io/ for any curious folks