Errors and diagnostics
02.03.01 2026-10-19 — Errors and diagnostics
Fact sheet for error tags and diagnostic chrome. This does not invent FPL language semantics or change the walker printer. Inspiration and sketches: Evaluation judgments. Live site: fpl-lit-scratch.
Judgment fail shape (locked, not printed)
|- ! err/<tag> : Error [@ <deadline>]!— fail marker on the judgment line (not falsum, not a source caret).err/<tag>— path under theerr/namespace (FPL/, not deadline).@ <n>— optional deadline (steps spent); see phrase costs / judgments.- Today’s TTY still uses
ERROR: <line>:<col> <message>.
HTTP status aliases
Optional numeric chrome where the HTTP gloss is honest. The path tag is the stable id for fixtures; the number may appear on a banner (err/out-of-gas 408).
| Tag | HTTP | Gloss |
|---|---|---|
err/out-of-gas |
408 | Request Timeout — meter / budget exhausted |
err/no-row |
404 | Not Found — nothing matched |
| (later) type / refuse | 422 | Unprocessable Entity |
| (later) internal | 500 | Internal Server Error — walker bug |
Do not assign a code for every slip. Path-only when no honest HTTP metaphor fits.
Clipper lore (chrome)
For err/out-of-gas / 408, Clipper (Kakoune Clippy face) may say: Immortal Joe is coming; look out for your ice cream, Jack. Full ASCII sketch in judgments.
Catalog
Grows as tags land. Printer and under-span ^ are not wired yet.