Tablets like the iPad are ideal for certain activities, but programming is not typically among them. Much like writing text, you can write code on the iPad, but it's more cumbersome without an external keyboard and you'll probably need to port your draft over to the desktop for it to be truly useful.
We don't expect to see developers ditch their laptops anytime soon, but a new breed of apps for the iPad help make the device more coding-friendly. One of them is Codify, which went live yesterday. It lets you build simple games and simulations using a combination of hand-coding and touch-based visual programming.
Coming from the game development shop TwoLivesLeft, Codify uses the lightweight Lua scripting language to build games that make the most of the iPad and iOS. Thus, creating games that utilize the accelerometer and multitouch gestures on the iPad.
During development, you can tap certain properties to define things like colors and images using a touch-based UI, rather than writing those things out in straight code.
The downside? The code you create in Codify can't be exported or compiled for use elsewhere. It's kind of just stuck there, thanks to Apple's current restrictions on iOS development. Still, it wasn't long ago that an app like Codify couldn't have existed at all on iOS, so it's possible those limitations will continue to loosen with time.