-- Backslash-lambda shorthand (`\x{body}`, `\x -> body`) from Haskell/Rust
-- is NOT valid ilo. Reaching for it surfaces ILO-L001 with a hint pointing
-- at the canonical parenthesised-lambda form:
--
-- `\x{body}` is a Haskell/Rust lambda shorthand.
-- ilo lambdas are parenthesised: `(x:t>r;body)`...
--
-- The right ilo shape is the same parenthesised lambda used everywhere else:
-- `(<param>:<type> ...><return-type>;<body>)`. Param and return types are
-- explicit (no inference at the lambda boundary).
-- Map every number to itself + 1.
inc-all xs:L n>L n;map (x:n>n;+x 1) xs
-- Filter to positives. The Haskell shape `flt \x -> >x 0 xs` is the
-- common reach; the right form keeps the lambda parenthesised.
positives xs:L n>L n;flt (x:n>b;>x 0) xs
-- Sort by length. `srt \s -> len s ws` would be the Haskell reach;
-- ilo writes the lambda inline with explicit types.
by-len ws:L t>L t;srt (s:t>n;len s) ws
-- run: inc-all [1,2,3]
-- out: [2, 3, 4]
-- run: positives [-2,3,-1,4,0]
-- out: [3, 4]
-- run: by-len ["banana","fig","apple","kiwi"]
-- out: [fig, kiwi, apple, banana]