>>52
You are wrong, ← is not one keystroke, but one symbol. := is two symbols. How many keystrokes a vector of symbols is (a name), depends on various software and hardware. (strictly speaking, only on the software, the hardware can always be emulated - but it is a question: where can software run without hardware?)
For example, ← was a combination of two keystrokes for me. ^V. An extra action must be taken for the first ← used. I could set up my editor, to type 'larrow' and get that symbol instead.
You said ← is more productive. I'll say that this is a problem only to programming languages which do not have flexible grammar; semantically retarded, in practice, horribly awful. Lisp is a family of programming languages which for each it is true that they're different than the aforementioned described ones. Lisp my friend. It is lisp which will amaze you by how much you're allowed to change her, without her changing at all!