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Parse LaTeX code

Source: R/parseLatex.R
parseLatex_fn.Rd

The parseLatex function parses LaTeX source, producing a structured object.

Usage

parseLatex(
  text,
  verbose = FALSE,
  verbatim = c("verbatim", "verbatim*", "Sinput", "Soutput"),
  verb = "\\Sexpr",
  defcmd = c("\\newcommand", "\\renewcommand", "\\providecommand", "\\def",
    "\\let"),
  defenv = c("\\newenvironment", "\\renewenvironment"),
  catcodes = defaultCatcodes,
  recover = FALSE
)

# S3 method for class 'LaTeX2item'
print(x, ...)

# S3 method for class 'LaTeX2'
print(x, tags = FALSE, ...)

Arguments

text

A character vector containing LaTeX source code.

verbose

If TRUE, print debug error messages.

verbatim

A character vector containing the names of LaTeX environments holding verbatim text.

verb

A character vector containing LaTeX macros that should be assumed to hold verbatim text.

defcmd, defenv

Character vectors of macros that are assumed to define new macro commands or environments respectively.

catcodes

A list or dataframe holding LaTeX "catcodes", such as defaultCatcodes.

recover

If TRUE, convert errors to warnings and continue parsing. See Details below.

x

Object to work on.

...

Extra parameters to pass to deparseLatex.

tags

Whether to display LaTeX2 tags.

Value

parseLatex returns parsed Latex in a list with class "LaTeX2". Items in the list have class "LaTeX2item".

Details

Some versions of LaTeX such as pdflatex only handle ASCII inputs, while others such as xelatex allow Unicode input. parseLatex allows Unicode input.

During processing of LaTeX input, an interpreter can change the handling of characters as it goes, using the \catcode macro or others such as \makeatletter. However, parseLatex() is purely a parser, not an interpreter, so it can't do that, but the user can change handling for the whole call using the catcodes argument.

catcodes should be a list or dataframe with at least two columns:

  • char should be a column of single characters.

  • catcode should be a column of integers in the range 0 to 15 giving the corresponding catcode.

During parsing, parseLatex will check these values first. If the input character doesn't match anything, then it will be categorized:

  • as a letter (catcode 11) using the ICU function u_hasBinaryProperty(c, UCHAR_ALPHABETIC) (or iswalpha(c) on Windows),

  • as a control character (catcode 15) if its code point is less than 32,

  • as "other" (catcode 12) otherwise.

When recover = TRUE, the parser will mark each error in the output, and attempt to continue parsing. This may lead to a cascade of errors, but will sometimes help in locating the first error. The section of text related to the error will be marked as an item with tag ERROR.

See also

LaTeX2, LaTeX2item

Examples

parsed <- parseLatex(r"(fran\c{c}ais)")
parsed
#> fran\c{c}ais