Dylan M. Taylor
d56a2a1cb3
The corpus equations go through OMML, MathML and LaTeX and back; the OMML samples are written back as kept and from the tree. GridCraft's OMML to LaTeX test cases (crates/xlsx/src/omml.rs) give LaTeX that reads back the same through the tree. omml::parse and read_str are tested against other prefixes, the strict namespace, kept OMML, junk, the element cap and deep nesting.
2.8 KiB
craft-math
Equations as one tree, and the syntaxes it is read from and written to:
| Module | Syntax | Read | Write |
|---|---|---|---|
math |
the tree: MNode, MRun, Math (an equation with its kept source OMML), modelled on the Office Math object model (ECMA-376 Part 1 §22.1) |
||
math_linear |
UnicodeMath, the linear format Word shows (x=(-b±√(b^2-4ac))/2a) |
math::parse_linear |
math::to_linear |
math_latex |
LaTeX math, including MathLive's spellings | parse_latex |
to_latex |
omml |
Office Math Markup (m:oMath, DOCX/PPTX/XLSX) |
read_omath, read_str |
write_equation, write_str |
mathml |
presentation MathML (HTML, ODF formulas, the clipboard) | parse, read, to_tree |
to_mathml, linear_to_mathml |
Beside them: math_symbols (LaTeX names of symbols), math_tree (the arguments of a node, a walk
over every run), symbol_fonts (Symbol, Wingdings and the other symbol fonts as Unicode) and
Rgb (a run's colour).
use craft_math::{Math, math, math_latex, mathml, omml};
let tree = math_latex::parse_latex(r"\frac{a}{b}+\sqrt{x}");
assert_eq!(math::to_linear(&tree), "a/b+√x");
// OMML out and back.
let eq = Math { nodes: tree.clone(), ..Default::default() };
let xml = omml::write_str("", false, &eq, None);
let read = omml::read_str(&xml).unwrap();
assert_eq!(read.nodes, tree);
// MathML carries the linear format in an annotation, so it reads back exactly.
let ml = mathml::linear_to_mathml("a/b+√x", true);
assert_eq!(mathml::parse(&ml).and_then(|m| mathml::read(&m)), Some(("a/b+√x".to_string(), true)));
Reading OMML
omml::read_omath takes an m:oMath element of a craft_xml tree read with the canonical
prefixes of omml::NAMESPACES (m, w and mc, transitional and strict URIs), so a document
reader passes the element it already has. omml::read_str and omml::parse read a string. The
source XML is kept in Math::omml; write_equation writes it back unchanged while the
equation's colour is the same and the XML is well formed, so a saved document carries the
equation as Word wrote it.
Limits
Nesting is bounded by math::MAX_DEPTH in every reader and writer; omml::parse reads at most
omml::MAX_ELEMENTS elements and mathml::parse keeps at most mathml::MAX_NODES; the LaTeX
reader looks at 20,000 characters. Nothing panics on any input.
Provenance
The tree, the linear format, LaTeX, the symbol names, the tree walk, the symbol fonts and Rgb
are WordCraft's (crates/doc), as moved into craft-wordmodel; OMML is WordCraft's DOCX reader
and writer (crates/docx/src/read/math.rs, write/math.rs) and MathML its formats crate's
(crates/formats/src/mathml.rs), moved onto craft-xml. The MathLive command spellings and the
round-trip corpus in tests/corpus/ come from equaSHion (storytold/craft-libs#29).