Use of “learnable programming” (via direct manipulation) software, in teaching I read something on this site, that lead me to read about Bret Victor's learnable programming and direct manipulation.
I was wondering if anyone has used any software like this.
What software have we used? What effect did it have on teaching and learning?
What is direct manipulation, also referred to as learnable programming
Victor tells us that the techniques that we now use, are based on best practice from the days of paper and pen, teletypes. That we have not yet adapted to this new media and what it can do. That typing a program, and then immediately running it, is not immediate enough. Output should change as code changes, not wait for us to press run. We should be able to manipulate the output, to change the code. Not just manipulate the code, to change the output.
 An example: Here we see the programmer, manipulating a variable, by using a slider. We the the effect on the output. We see the effect over time. The programmer is trying to give the turtle the correct bounce, so that the jumping character will be able to get through the gap. The programmer no-longer had to do long calculations, or do guess/change/run cycles. Whey just slide the slider until they see what they want.
see:

Invention on principle (programming perspective)
Stop drawing dead fish (an art perspective)
The future of programming (a historic perspective)
LearnableProgramming good blog post on teaching and learning progrmming


Preference is for Free Software, that is software with freedoms, not with zero price (I do not introduce proprietary software into my school).
App Inventor syncs with a tablet so that as students change the app's code, it changes the app running on the tab. It can't auto-sync media, so you have to re-sync the app when you add new sound or pics. It syncs via wireless network or usb. 

Khan Academy offers this slider concept with its Javascript Animation lessons.