-- Top-level imperative chains need a `main>_;` wrapper.
--
-- Personas reach for a Python-style imperative chain at the top level:
--
-- pts=gen-pts
-- cs0=[[4.8 4.9][6.2 7.1]]
-- cs1=iter cs0 pts
-- prnt cs1
--
-- In ilo every binding has to live inside a function body. Without a
-- header to anchor the chain, the parser either dies on the bare `=`
-- (ILO-P003) or slurps the whole chain into a previous function's
-- body and emits a cascade of misleading ILO-T005s.
--
-- ILO-P102 catches this shape at parse time and points at the fix:
-- wrap the chain in `main>_;`. The same code, with one header line on
-- top, runs cleanly.
-- The fixed shape: `main>_;` is the conventional zero-arg entry point.
-- `_` tells ilo to infer the return type from the body.
main>_;pts=[1 2 3];cs0=[4 5 6];cs1=pts;prnt cs1
-- run: main
-- out: [1, 2, 3]