-- Canonical conditional shapes in ilo. This file is the in-context
-- learning example that backs the reserved-word hint
-- `?expr{true:...;false:...}` (ILO-P001 on the `if` keyword). When the
-- hint suggests a syntax shape, that shape MUST round-trip through
-- the parser — otherwise an agent's first retry hits a second error
-- and burns tokens. This example pins the three canonical shapes
-- agents can reach for in place of `if/else`.
-- Shape 1: bool match with explicit `true:` / `false:` arms.
-- This is the shape the `if`-reserved-word hint points at. Arms are
-- separated by `;` (NOT a space) — the same rule as every other
-- `?subj{...}` match form.
m1 h:b>n;?h{true:1;false:0}
-- Shape 2: bare-bool ternary `?subj{then}{else}` — two positional
-- brace blocks, no `true:`/`false:` labels. Cheaper to generate when
-- both arms are single expressions.
m2 h:b>n;?h{1}{0}
-- Shape 3: bare-bool prefix ternary `?subj a b` — no braces at all.
-- Cheapest shape (6 chars for `?h 1 0` vs 8 for `?h{1}{0}` vs 12 for
-- `?h{true:1;false:0}`). Use when both arms are bare atoms.
m3 h:b>n;?h 1 0
-- Shape 4: general `?h cond a b` prefix-ternary keyword — three
-- operand atoms after the literal `?h`. The first operand is the
-- condition; the next two are then/else. Use when the condition is
-- a more complex bool expression than a single ref.
m4 x:n>t;cn=>x 0;?h cn "pos" "nonpos"
-- All four shapes return the same value when fed the same condition.
-- The four-way redundancy is deliberate: agents land on whichever
-- shape they prefer, and the parser accepts any of them without
-- forcing a rewrite.
-- run: m1 true
-- out: 1
-- run: m1 false
-- out: 0
-- run: m2 true
-- out: 1
-- run: m2 false
-- out: 0
-- run: m3 true
-- out: 1
-- run: m3 false
-- out: 0
-- run: m4 5
-- out: pos
-- run: m4 -1
-- out: nonpos