Trace Controls ⎕TRACE
Dyadic ⎕TRACE means

Set Trace Controls

      +(0,⍳10) ⎕TRACE 'foo'
0 1 2 3 4 5
Monadic ⎕TRACE means

Query Trace Controls

      ⎕TRACE 'foo'
0 1 2 3 4 5

Language Elements