For -12h timestamp, why does the "ts.date" syntax not work within a function?

I am trying to get the 30-second multiple of a timestamp:

q)ts:2025.02.14D11:09:31.033
q)ts.date  + 30 xbar `second$ts
2025.02.14D11:09:30.000000000

When I do this in a function it behaves differently:

q)f:{[t]: t.date  + 30 xbar `second$t}
q)f ts
2000.01.02D11:09:30.000000000

Notice how the date has been lost here and turned into 2000.01.02

Can someone explain what is happening here?

Solution

This is because

Unfortunately, at the time of this writing (Sep 2015) dot notation for extraction (still) does not work inside functions.

just refactor your code and this should work

f:{[t]: $[`date;ts]  + 30 xbar `second$t}
f ts
2025.02.14D11:09:30.000000000