Nushell core team meeting 2022-06-08

Attendees

• Darren
• Michael
• Jakub
• JT
• Reilly
• Stefan
• Andrés

Open topics

Discussed topics

• Compiler design lessons from jakt selfhost

  • Having a compiler stage struct that contains a list of errors to add.

• Error convenience

  • Errors in a traceback
  • Experience currently depends heavily on the quality of the individual error emitting locations

• Despanning

  • Lets try to move from value.span() to expr.span() instead of doing the hard refactor first
  • not carrying spans on Value should reduce the memory footprint and thus improve performance.

• Flag passthrough

  • Should externs pass undocumented/able flags
  • Problem: positionals vs values for flags
  • Ordering has to be preserved! (Tools might only accept flags and positionals in a particular order)
  • ?: Workaround with annotations for the parameters or flags with ^

• Optimization for REPL vs IDE

  • Nushell is very static + deltas as an optimization for the repl but this is hard if we want to do IDE support for larger scripts.
  • Maybe take inspiration from jakts IDE approach
  • Treesitterability of nushell

• Performance monitoring

  • Jakub introduced $nu.scope.engine_state to get statistics about what the engine is holding
  • We probably need a GC sooner rather than later.
  • Can we serialize stuff as parquet to keep the hot memory smaller.
  • Great place for serialized data might be last_result

• Data(frame) optimized engine tradeoffs

  • Datafusion style engine
  • Sequential optimized shell engine
  • Dataframe highly efficient on a special subset of problems
  • How can we get nushell commands to dispatch on all different data representations.

• SQlite history part 2 (land it in nushoell)

  • landed in reedline, nushell not yet adapted to the new API (independent of whether a text file or sqlite is used)
  • Goal: have the option in the config to toggle on the new history to test it. (Currently no tangible benefit yet)
  • Some TODOs in phiresky's code, porting of the history command.
  • Benefit of making it a compiler flag instead of config flag is minimal as the API adaptations have to be done anyways