Entry 23

Areas in one line each and files that fold

2026-09-24specsite

Filescrates/cairns-core/src/config.rscrates/cairns-site/src/html.rscrates/cairns-site/src/assets/style.cssdocs/spec/config.md

Two complaints from use, both about friction rather than correctness: adding an area was a chore, and an entry with fifteen files put a wall of paths between its title and its first sentence.

[area] as one table

An area is a name and a phrase, and [[area]] spent three lines and two keys saying so. cairns.toml now also takes a single table:

[area]
spec = "the format itself - entries, config, log.json, publishing"
core = "cairns-core: parsing, validation, the canonical document"

The [[area]] list is still read and means the same thing. It is deliberately documented as the long form rather than an old one: each area there is its own table, so a key added to areas later has somewhere to go, and the short form only has room for about. TOML refuses a file holding both, so there is nothing to reconcile.

Both forms go through one hand-written visitor, areas in config.rs, rather than an untagged enum - an untagged enum reports "data did not match any variant" and throws away TOML's own message about what was actually wrong.

The order matters, since it is the presentation order in the filters, the skill and the index. I expected to need the toml crate's preserve_order feature for that; I did not. toml 0.8 hands a visitor the keys in document order regardless - the feature only changes the order of its own Table type. an_area_table_reads_in_the_order_written holds it, with areas declared non-alphabetically.

A name declared twice is now an error in either form. The table form gets that from TOML for free; the list form never checked, and now validate does.

The cheaper half of "adding an area is annoying" was the error message. cairns new --area nope now ends with the line to paste:

to add it, write this under [area] in cairns.toml:
    nope = "what belongs here"

It says [area] even to a config written in the long form, because the parsed config does not remember which form it came from. Not worth a flag.

cairns init writes the short form, and this repo's own config uses it.

Files, grouped and folded

The entry page printed files as one wrapped row of full paths. Most of the length was the same crates/x/src/ repeated. Now each directory is said once, muted, with the names after it, and the full path is on hover. Past five files (FILES_SHOWN in html.rs) the list is a <details> that starts closed, labelled with its count - "15 in 7 directories" - and opens to one directory per line. No script.

A path with a trailing slash is a directory and is named by its last component under its parent, so docs/spec/ shows as spec/ under docs/, not as an empty group under itself.

Checked with the render loop from 13, against a copy of this log with entry 22 given fifteen files, open and closed. The first screenshot showed the filename inside a code chip and the directory outside it, which read as two unrelated things; the chip is gone inside .files. Tests: an_entrys_files_say_each_directory_once, a_long_list_of_files_folds_behind_its_count.