pulldown-latex

A pull parser for $\LaTeX$ parsing and mathml rendering.

This project is inspired Katex, Temml, MathJax, etc. It is in its very early stages of development, and works for a small subset of what Katex and the likes support. It is not production ready and is mostly untested.

Goals

Follow modern LaTeX principles: Ideally, this library should be mostly compatible with latex2e and amsmath. The term mostly is used here to refer to the mathematical commands exposed by these packages; typesetting prose is out of scope for this crate. Another consequence of this goal is that some plain-TeX commands that are deprecated (e.g., \atop, \over, etc.) are not supported by this crate.

Closely resembling conventional LaTeX: It is a goal for this crate to make efforts in generating aesthetic equations. This means that the mathml output may be tweaked to make it resemble what pdflatex, Katex or MathJax outputs.

Miscellaneous References & Tools

Sources used during the development of this crate. Any reference in code comments refer to these links specifically.

• TeXBook
• latex2e unofficial Reference
• amsmath docs
• Comprehensive symbol list
• Unicode-math symbol list
• Unicode-math package page
• Font tester
• Math Variant Selection

To Test

• All the things temml and katex test
• Cargo Mutants
• Errors

Unsupported Plain-TeX & LaTeX behavior

• Changing catcodes of characters
• \if* macros
• ^^_ & ^^[0-9a-f][0-9a-f] as a way of specifying characters
• Redefining active characters This library currently only supports default active characters, and hence does not allow for the definition of active characters.
• Implicit characters as whitespace tokens As in the TeXbook p. 265, Knuth specifies that a space token stands for an explicit or implicit space. This library does not currently support implicit space tokens when a space token is required.
• Use of internal values and parameters, such as registers, and things like \tolerance (See TeXbook p. 267 for a complete definition)
• \magnification parameter & true sizes
• Case insensitive keywords matching. According to TeXbook p. 265, keywords such as pt, em, true, etc. are matched case insensitively (e.g., pT would match pt). This library does not support this behavior, as keywords must match exactly (i.e., em, true, pt, etc.).
• fil units TeX allows the use of fil(ll...) units, this library does not.
• \outer specifier on definitions
• \csname & \endcsname
• \begingroup and {, and \endgroup and } behave the same way; that is to say, \begingroup and \endgroup do not have the property of "keeping the same mode" (TeXbook p. 275).
• All vertical list manipulation commands. Things like \vskip, \vfil, \moveleft etc.
• \hfil, \hfill
• \eqno, \leqno, and equation numbers in general.
• \over, \atop, and all deprecated "fraction like" control sequences.

Things that should work but don't currently

Splitting groupings within user defined macros. E.g.,

\def\abc{\left(}
\abc 4 \right)

This currently does not work.

Unsupported Katex/Temml Options

• Macros preamble
• Wrap
• Left equation numbers
• colorIsTextColor
• ThrowOnError
• maxSize
• trust
• \toggle groups