Accessing element from Stream in agda

问题

I have made a stream of (N x N) type. How can i access the individual element of the pair ??

genL : ℕ →  Stream (ℕ × ℕ) →  Stream (ℕ × ℕ)
genL k ((x , y) :: xs)  = if ((y * k) lt x) then (x , y) :: (♯ genL k (♭ xs))
                          else genL k (♭ xs)

It says there is no constuctor , in stream. I have one solution in mind that i will create records of pair then it will works. Apart from that is there any other way to acccess the element.

回答1:

The constructor is _∷_ (type \:: to get ∷), not _::_.

Anyway your definition is not productive and doesn't convince the termination checker.

来源：https://stackoverflow.com/questions/29369643/accessing-element-from-stream-in-agda