Autocomplete Slice #1: write visitor to determine values that may exist for each input

[twschiller]

[This issue was automatically opened using ProductBoard.]

Give variable usage assistance in the page editor with autocomplete.

This issue is for Slice 1.

Specification:

https://www.notion.so/pixiebrix/Autocomplete-Autosuggest-Expressions-270c903d6bf043848fd1a3dcd4cffe45

• Slice #1: write visitor to determine values that may exist for each input

  • Write an analysis visitor that compiles the following information. (Needs to construct a lattice of types for may/must analysis)

    • Declared Output keys of previous steps → evidence that output key is available

      • Later steps with same output key override previous steps

      • Assumes the output schema of the brick. If no output schema, assume any

    • The Context from the previous run. (Or the Context of the previous brick + output key) if not run yet

    • Bonus: if expression is used as an input to a brick, can infer that the input satisfies the inputSpec in later bricks. (Otherwise it would throw a dynamic validation error before getting to that brick)

    • Need to handle the For-Each, Try-Except, etc. bricks that introduce additional output keys

  • Week 42: 5 points

  • Week 43: 3 points remain

[twschiller]

Link to subfeature: https://pixiebrix.productboard.com/feature-board/planning/features/15728980

[corinnemayans]

I meant to title this "Autocomplete Slice 1", but it won't let me edit the title since it thinks Todd opened it...

[corinnemayans]

Please post Loom to #sprint-demo when complete.