future-plans: add field value parser chain and long-term cache note

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

future-plans.md

@@ -38,15 +38,39 @@ function and own their local state.
 
 ## Field system
 
-### Field rendering integrations
-`render_field_value()` in `app.mjs` is the central place for field display logic.
-Planned extensions:
+### Improvements
+
+#### Field value parser chain
+Similar to how name formatters use a template chain, field values could be passed
+through a parser chain that returns structured data based on field name/type hints.
+Examples:
+
+- A field whose name contains `tolerance` could parse `20` as `{ negative: 20, positive: 20 }`
+  and `-10/+30` as `{ negative: 10, positive: 30 }`
+- URL detection (currently hardcoded in `render_field_value()`) could be one parser
+  in this chain rather than a special case
+- Mouser/Digi-Key part numbers could be detected and return a structured link target
+
+The parser chain would mirror the template system: user-defined or built-in parsers
+keyed by field name pattern, tried in order, returning structured data or `null` to
+pass through to the next. `render_field_value()` would then receive parsed data and
+render accordingly.
+
+#### Field rendering integrations
+With or without a parser chain, `render_field_value()` should gain:
 - Mouser/Digi-Key part number fields → auto-craft links to product pages
 - More URL-like patterns (without `https://` prefix)
 
-### Field types
-Currently all field values are free-text strings. Could benefit from typed fields
-(numeric, enum/dropdown) for better formatting and validation.
+### Long term
+
+#### Renderer/parser result cache
+Once parsers and formatters run per-render, a cache keyed on field value + template
+version would avoid redundant work on large inventories. Invalidated when any
+template changes. Not urgent — premature until the parser chain exists.
+
+#### Field types
+Currently all field values are free-text strings. Typed fields (numeric,
+enum/dropdown) would enable better formatting, validation, and range-aware search.
 
 ## PDF / files