Module oml 

OML (Omnist Markup Language) – the native codec for the Document model.

Ported from ~/dev/omnist/omnist/oml.py (issue #10). OML is omnist’s own serialization format: every Document – every ordered, possibly-repeated, possibly-interleaved edge list, and all seven scalar kinds (string, integer, number, boolean, date, time, datetime) plus null – round-trips through OML exactly, with no adjustment ever needed (unlike JSON/YAML/TOML/XML).

This module implements the OML-Core grammar in full for both read_oml and write_oml, plus the OML-Extended raw-string ('...', E2) and triple-quoted multiline-string ("""...""", E3) spellings on read only – write_oml only ever emits OML-Core double-quoted strings, matching the Python reference.

Layout (issue #53)

scanner tokenizes source text, parser consumes those tokens into a RawNode, and writer renders a RawNode back to OML-Core source. This top-level module keeps the module doc overview, the four pub fns (read_oml, write_oml, write_oml_compact, check_oml), and the Codec adapter – nothing about crate::oml::* paths changed by the split.

Architecture (per issue #1/#10, “architecture freedom”)

Python’s reader is a single-pass scanner built around one compiled “master” regex, deferring line/col computation and scalar-value construction until actually needed – a Python-performance-specific design (see the module’s PR #168 for the profile that motivated it), not a behavioral requirement. This port uses a straightforward hand-written recursive-descent scanner/parser over byte-indexed &str instead: idiomatic Rust, and there’s no equivalent hot-path reason to defer decoding here. Observable behavior (parse results, round-trips, error content) matches the Python reference; exact error wording does not need to.

Node representation

crate::document::RawNode – not crate::document::Value – is the type this codec reads into and writes from. Value::Object’s IndexMap can’t hold a repeated key, so it only represents “repeated label” as a contiguous run (an array value under one key); OML must round-trip arbitrary interleaving of repeated labels losslessly (its whole reason for existing – “no adjustment ever needed”), which only RawNode’s literal edge list can hold exactly.

Depth guard (omnist-ts#37 / omnist-ts#70)

write_oml takes a plain, unchecked crate::document::RawNode – exactly like Python’s write_oml(node), which accepts any hand-built canonical node, not necessarily one that passed through a depth-checked builder. So the writer calls the shared crate::document::check_write_depth guard itself, at every nesting level, rather than assuming its input already got checked somewhere upstream – the exact bug class omnist-ts#37/#70 were: a writer (or a second writer) that skipped this because some builder happened to guard depth already.

Functions

check_oml

Report what writing OML would adjust, without producing output. Added for issue #31 (the format registry): OML is lossless for every Document (see this module’s doc comment), so there is never anything to report – mirrors Python’s check_oml, which is exactly return WriteReport(). Every other builtin format has a check_* function already; this is the OML counterpart, needed so the "oml" registry entry has a check callable like the other four.

read_oml

Parse OML source into a canonical RawNode (edge-list or leaf).

write_oml

Render a canonical RawNode as OML-Core source, pretty-printed with indent spaces per nesting level.

write_oml_compact

Single-line (“compact”) rendering: edges joined by "; ", no newlines/padding. Mirrors Python’s write_oml(..., indent=None). Both forms round-trip through read_oml.