Hi, 

Could someone please point out what is the difference between using $ and parenthesis in the function composition below. Why does the first expression work whereas the second fails.
---
$$ head.head$[[1,2],[3,4]]
1
$$ head.head([[1,2],[3,4]])

<interactive>:122:12:
    Couldn't match expected type ‘a -> [c]’ with actual type ‘[t0]’
    Relevant bindings include
---
Thanks,
Shishir