Stored programs

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Programs are plain text. Store them with the answer and they render again later, on any client, as long as the catalog keeps the rules below.

The message format

OpenUI.Message writes and reads the format of prompt.md, section 7: the program between marker lines the model never sees.

stored =
  OpenUI.Message.build(
    content: program,
    context: [state],
    attributes: [{"library", "support@1.2.0"}],
    end: true
  )
]]>openui:content?library=support%401.2.0
root = Stack([open])
open = Metric("Open tickets", 12)
]]>openui:context
[{"$tab":"open"}]
]]>openui:end
  • content: the program, or prose with fenced programs.
  • context: anything the host wants; the renderers store the page state here, as [state].
  • end: the stream finished. A message without it was cut, and still renders.

OpenUI.Message.parse/2 reads it back. When a response was regenerated after a failure, the last content wins. The LiveView renderer accepts the stored form directly in response and restores the state from its context.

State

The renderer sends {:openui, id, {:state, state}} whenever the person changes something. The state holds $variables with their values and form fields as %{"value" => ..., "componentType" => ...}, in the same shape the official React renderer uses, so a message stored by one renders with its state on the other.

Restoring never fails: keys the program no longer declares are kept, and values of an unexpected type are passed to the components as they are.

What the model sees

History sent back to the model must not contain marker lines:

OpenUI.Message.model_text(stored_answer, :assistant)
OpenUI.Message.model_text(stored_click, :user)

Keeping old programs readable

Position is the meaning of an argument. A program stored today calls Metric("Open tickets", 12); if Metric later takes value first, that program shows the wrong thing. The rules of prompt.md, section 3.2:

  1. Only add props at the end. Never reorder or remove one.
  2. A new required prop needs a default, since old programs cannot pass it.
  3. Never name anything after a new built-in.

mix openui.gen.spec MyApp.Library --out library.json --check enforces the first two in CI by comparing the module with the committed spec.

Edits

In edit mode the model answers with only the statements that changed. Merge them once the patch finished streaming:

new_program = OpenUI.Edit.merge(current_program, patch)

A statement with an existing name replaces it, a new name is added, name = null deletes, and what root no longer reaches is removed. Store the merged program.