Tolerant on input
Accepts the Markdown people actually write — irregular spacing, mixed emphasis markers, the usual GFM extensions — and models it in a strict, unambiguous AST. Forward-only scanning, bounded lookahead, no backtracking.
One meaning,
one form.
Markdown stays nice, and becomes reliable. Markanto reads familiar Markdown tolerantly, gives it a strict semantic structure, and writes it back in exactly one canonical form per meaning.
NOTES.MDMARKANTO 0.1.0# Release notesWritten with *emphasis*, a[link](/spec/), and one**strong** marker to fix.FORMAT → CANONICAL · 0 diagnostics
01 / What it is
Lenient input.
One output.
Read tolerantly, model strictly, serialise canonically. CommonMark standardises how Markdown is read; Markanto also standardises how it is written — it keeps the loose input authors expect and removes the loose output.
Exactly one output
One way to write each construct back out. Reformatting is idempotent; two authors who mean the same thing produce identical bytes.
A pure AST check
Undefined footnote references, ID uniqueness, resource-attribute allowlists, quote nesting, table shape, the inline structural invariants — a function over the AST, independent of the parser.
Why not just Markdown? Markdown standardises how a document is read — never one way to write it back. Markanto adds a strict semantic structure and exactly one canonical form, so tools, pipelines, and agents transform a document and get the same bytes every time — and it stays Markdown you write by hand. A library models Markdown for one tool; Markanto makes that model a shared contract.
02 / The laws
Three laws hold.
The canonical form is not a style preference. It is the property the parser, formatter, and validator are built to guarantee.
Semantic round-trip
parse(format(doc)) is semantically equal to doc. Formatting never changes meaning.
Idempotent
format run twice changes nothing the first run didn’t. The canonical form is a fixed point.
Equivalent input, same AST
Non-canonical and canonical spellings of the same meaning parse to the same AST — and format to the same bytes.
03 / Degradation
Still readable
as Markdown.
Markanto-specific syntax is designed to degrade gracefully: in a plain Markdown renderer it should lose its meaning, never its readability. The canonical form stays machine-friendly without becoming machine-first — it is still Markdown a person writes by hand.
<m> <i> <b>
Three wrapper tags, not raw HTML
The whole reserved vocabulary is <m> (metadata / resources), <i> and <b> (emphasis fallbacks) — the mnemonic is MIB.
They are Markanto syntax, not a general HTML passthrough. Canonical output still prefers
*em* and **strong**.
No plugin semantics
Meaning travels with the document
No added syntax, no compatibility aliases, no parser profiles that alter meaning, no heuristic media typing. An external profile must not change how identical source text is interpreted.
04 / Numbers
Numbers instead
of adjectives.
Idempotent reformatting, stable diffs, and safe automated rewrites are only worth as much as the guarantees behind them. What those rest on, counted.
Measurement0.1.0
Conformance corpus583cases · normal + strict
Test suite1,898tests, plus
verify:nodeCommonMark 0.31.2 / GFM classified672vendored cases · 0 fail
Property soak100kseeded docs per stream
Reserved wrapper tags3down from 7 in the 0.5.3 drafts
Runtime dependencies0root entry point
The language design and specification were independently audited (2026-08-30); an independent whole-repo
review of the implementation returned a
SHIP / FREEZE
verdict — 0 blockers, 0 retained major findings. The full gate list is in the
changelog,
and every v0.5.3 → 0.1.0 language delta is in
EVOLUTION_V053_TO_010.md.
05 / Resource safety
Built for documents
that tools touch.
Formatting, validation, and automated rewrites stay predictable because meaning, canonical output, and
resource limits are separate contracts. Every operation returns a tagged
status union; a resource budget being exceeded is always distinct from the document being invalid.
status: "resource"
A bounded work budget
The Grid occupancy matrix is bounded by a caller-tunable default (DEFAULT_MAX_MATRIX_SLOTS, 100 000) and an absolute, non-overridable ceiling (HARD_MAX_MATRIX_SLOTS, 1 000 000). An over-budget matrix returns resource, never a native RangeError.
O(n) target
Linear-time parsing
A monotonic cursor, no backtracking over competing interpretations. The property gate includes a parser-linearity probe. The architecture is written to port mechanically to safe, idiomatic Rust.
06 / Implementation
One reference
implementation.
TypeScript defines the AST, the canonical serialisation, and the conformance corpus any other implementation would be checked against. A Rust port is a deliberately kept-open option, not a current commitment.