There's no way to evaluate `def`s for `q::lastTrace` in the REPL

[bugarela]

The REPL is great for doing trace evaluation at low implementation cost. I was trying it out yesterday and I found it frustrating that I couldn't get the value of my defs and vals over the trace.

I wrote:

q::lastTrace.foldl(List(), (acc, state) => acc.append(projectState(state)))

but projectState has to be a pure operator that manipulates the state record, since it has no actual access to read the variables from each state.

It would be great to have a more user-friendly way of evaluating/projecting traces (that is, without requiring foldl) that allows projecting the values of defs and vals

Workaround

I can rewrite any def operator as a pure def operator that receives the state (or part of it) as a parameter, and then use the pure def in the projection.