Novice Question About u.q

Community Support
1

I was examining the u.q library and see this line:

[t;x]each w t

What does this mean exactly? For each w t pairs?
2. What is w here as I see it is not an argument of the function? Regarding the (neg first w) I assume that this is supposed to be a handle? If so where is it coming from?
3. The each is passing 2 params to the lambda but the lambda is expecting 3, do I miss something?
4. I couldn’t get; any elaboration is appreciated.
sell[x]w 1

Thanks in advance!

2

read the code  right to left::

first w@t

the result is applied applied one by one to the projected function (not all arguments fixed)