Add the generalized Pratt parsing example

[chengluyu]

No description provided.

[LPTK]

Looks like the test outputs are not up to date.

[LPTK]

The name is quite confusing. Why not

Suggested change

	fun derive(iterable, makeNext) = Iterable of () =>
	fun adaptIterator(iterable, makeNext) = Iterable of () =>

[LPTK]

Also why does it require all callers to wrap things in an obfuscating () =>?

[chengluyu]

I guess you're referring to the second parameter. This function takes the old iterator and produces a function that is going to be used as the next method on the new iterator. That's why it's called makeNext.

In summary, the function derive does the following things:

• takes an Iterable,
• creates an iterator by calling its Symbol.iterator,
• passed the iterator to makeNext, and
• uses the produced function as the next method on the new iterator.

[chengluyu]

(I didn't use the Commit suggestion feature to make the changes because the references below also needs to be updated.)