Design expression system for procedural animation

[Sportinger]

This discussion continues the idea from the original issue:

• Original issue: https://github.com/Sportinger/MasterSelects/issues/66
• Topic: an expression system for procedural animation and parameter automation.

Context

The original request was intentionally broad: an expression system that should feel comparable to After Effects expressions or a small Python-like scripting layer.

That is an important product direction, but it is not yet a concrete implementation issue. Before cutting buildable tasks, the design needs discussion.

Possible goals

• Drive transform/effect parameters from expressions.
• Reference time, clip properties, layer properties, keyframes, project values, and maybe media metadata.
• Support reusable snippets or presets.
• Keep expressions deterministic enough for export parity.
• Avoid unsafe arbitrary code execution in the browser.
• Provide useful errors and editor tooling instead of silent failures.

Open questions

• Should the language be JavaScript-like, After-Effects-like, Python-like, node-based, or a restricted custom DSL?
• Which properties should be expression-addressable first?
• How should expressions interact with keyframes?
• How do we guarantee the same result during playback, scrubbing, and export?
• What sandboxing/performance limits are needed?
• Should expressions become part of project serialization and versioning?

Recommendation: keep this as an Ideas discussion until the language model, security model, and first implementation slice are clear. Then create focused issues for the first concrete pieces.