ADR-0020 amends ADR-0001 with a two-phase parse: a lexer
producing a span-tagged token stream, then chumsky over
&[Token]. Single source of truth for keywords and punct via
a define_keywords!/define_punct! macro pattern. Parser
contract committed for I3 (queryable expected-token-set)
and I4 (lexer always succeeds, Error tokens for invalid
input). Includes an honest history note: the no-lexer shape
in dsl/parser.rs arose incrementally without ADR-level
deliberation against the known H1a/I3/I4 requirements; this
ADR corrects that.
ADR-0021 builds on ADR-0020 to close the H1a gap: a
per-command UsageEntry registry keyed off entry-keyword,
with parse errors rendered as caret + structural error +
matching usage template(s). Multi-entry families (add,
drop, show) render together. New catalog sections under
parse.usage.* (per-command grammar) and parse.token.*
(single-token vocabulary). Zero-prefix case ("frobulate
Customers") falls back to an "available commands:" framing.
Anchor-phrase compliance preserved.
claude@clouddev1