Turn Run off where there is nothing to run

[onatozmenn]

Follow-up to #30, which was not the fix.

Explaining the refusal after the fact is still telling somebody afterwards. Twenty-two of the twenty-nine examples are libraries, so for most of the corpus the first thing a reader does is press a button that cannot work.

The picker knows now. examples/index.json records, per example, whether it has a main and how many tests it has, and Run is off before it is reached for, with the reason beside it:

A library: no main to run, 3 tests to press Test on.

Both facts are asked, not guessed

tools/examples.mjs runs the pinned artifact over each file and reads its answer. Looking for fn main in the text would be a small parser written here, which is the thing this repository does not do.

$ node tools/examples.mjs
29 examples at v0.2.2: 7 with a `main`, 22 libraries.

It is a maintenance script, run when the pin moves, alongside the two commands already documented for that. tools/check.mjs fails if any entry is missing summary, runs or tests, so an index regenerated by an older version of the script cannot ship quietly.

The button comes back

The moment the text is edited, because what was known was known about the example and not about whatever it has become. A shared link is not an example either.

The note added in #30 stays, for a program somebody wrote themselves with no main. That is the path that cannot be known in advance.

Checked

example	Run	note
calendar	off	A library: no main to run, 3 tests to press Test on.
tic_tac_toe	off	A library: no main to run, 3 tests to press Test on.
hello	on
todo	on

Then typing one character into calendar: Run on, note gone.

_{Written with AI assistance.}