I've gotten bug reports for Hackety Hack where people say "I can't copy and paste from the lessons. Can you fix that?" I reply (obviously at more length and warmth) "Working as intended."
> You must type each of these exercises in, manually. If you copy and paste, you might as well just not even do them. The point of these exercises is to train your hands, your brain, and your mind in how to read, write, and see code. If you copy-paste, you are cheating yourself out of the effectiveness of the lessons.
I still think it's kind of amazing how such simple advice can be so effective. I often find that when I'm struggling to grok a new language or framework, that I've forgotten to hand-type at least a few examples.
The part of the body that learns how to program[1] doesn't speak English. You hear it even in the metaphors programmers use: code smell, this "feels" like a recursive problem, "listen to your code," etc.
That means to learn as quickly as you can you want as many parts of your body involved -- the English-speaking part, your muscles, your eyes, your memories of all the times you've made a stupid mistake only to have it cause you hours of frustration down the road, etc.
[1]: Really, the part of the body that learns anything doesn't speak English. English is just the data exchange format. ;)
Also, I don't know many professional programmers who type everything in by hand. It'll be something copied from a previous project, or cribbed from the documentation / somewhere online, then hacked into shape.
Of course, in order to do any of that you need to understand what's going on, but there might be easier ways to do that than manually typing in code.
Just because they're learning to code, doesn't mean that you should put artificial hurdles in front of them.
My pet theory is that it has something to do with information compression in the brain, kind of like Huffman coding, except you keep the table for life.