echo26

echo26 (Echo 2026 executable contract)

Echo 2026 is the language edition and canonical public Language Spec (ADR 0015). This directory is the machine-checked contract of that edition.

File-backed language fixtures. The suite runner is e26 (not linked to any one implementation). Point it at any Echo-compatible candidate binary.

Policy: every language implementation change updates this suite and keeps e26 green. See docs/fixtures.md, docs/testing.md, and AGENTS.md.

cargo build -p xo -p e26
cargo run -p e26 -- --binary target/debug/xo

Third-party toolchain:

e26 --binary /path/to/my-echo

Layout

echo26/<area>/<feature>/<NNN>_<slug>.echo
echo26/<area>/<feature>/<NNN>_<slug>.lex     # token kinds (required)
echo26/<area>/<feature>/<NNN>_<slug>.ast     # AST kinds (required)
echo26/<area>/<feature>/<NNN>_<slug>.diag    # optional lex diagnostic codes

Areas: leaders/, parse/, check/, multi/ (multi-file entries + support modules).

Only NNN_*.echo files are suite roots; unnumbered .echo files are imports only.

Candidate protocol

$binary lex --kinds --diag-codes path.echo
  stdout → .lex    stderr → .diag

$binary ast --kinds --diag-codes path.echo
  stdout → .ast

$binary check --diag-codes path.echo
  stderr → .check   # `sem-*` only; omit file if none

Update expectations from a known-good binary:

e26 --binary target/debug/xo --update

Filter:

e26 --binary target/debug/xo --filter leaders/bind

Details: docs/fixtures.md.