-- N prefix operators take N+1 operands, not N. The qa-tester P1 rerun
-- used the wrong arity, e.g. `+++a b c` with three operators but only
-- three operands. That used to unwind silently into a bare ILO-P010
-- "expected expression, got EOF" at line 1 col 1, leaving the agent no
-- signal about where to look. The parser now emits a clean ILO-P003
-- pointing at the chain head with the actual glyph and the shortfall,
-- so the next attempt can supply the missing operand or reshape.
--
-- Two canonical fixes when an agent reaches for a deep prefix chain:
--
-- 1. Provide K+1 operands. `+++a b c d` (depth 3, 4 operands) parses
-- to ((a+b) + c) + d.
--
-- 2. Bind intermediate results, which is also more token-efficient
-- once a chain gets past two ops: `s=+a b;t=+s c;+t d` builds the
-- same value left-to-right and reads obviously.
--
-- The example below uses both forms so an agent encountering this file
-- has a working template for either approach.
deeparity a:n b:n c:n d:n>n;+++a b c d
deepbind a:n b:n c:n d:n>n;s=+a b;t=+s c;+t d
-- run: deeparity 1 2 3 4
-- out: 10
-- run: deepbind 1 2 3 4
-- out: 10