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Wrap standard text for math-first LaTeX renderers

Source: R/utils.R
latex_wrap.Rd

Parses character strings to safely isolate standard natural language from LaTeX math environments. Standard text is wrapped in \text{} blocks, while equations, display math, and specific LaTeX environments are preserved verbatim. This is heavily optimized for passing mixed-content strings (like plot titles or axis labels) to pure-math typesetting engines like MicroTex. The conversion is not perfect, but it should handle most common cases without user intervention.

Usage

latex_wrap(tex, input_mode = c("mixed", "math"))

Arguments

tex

character. The string or vector of strings to be processed.

input_mode

character. A length-one character vector dictating the parsing strategy. If "mixed" (default), the string is tokenized and text is wrapped. If "math", the parser is bypassed and the string is returned unmodified, assuming the user has provided a pure math equation.

Value

A character vector of the same length as tex, formatted for math-mode LaTeX rendering.

Details

latex_wrap() operates as a state-machine tokenizer to ensure that valid LaTeX math is not corrupted by the text-wrapping process. It features:

  • Delimiter Preservation: Standard inline ($, \() and block ($$, \[) math delimiters are recognized and preserved.

  • Environment Tracking: Complex nested environments (e.g., \begin{matrix}) are safely extracted and bypassed.

  • Newline Conversion: R newline characters (\n) occurring outside of math environments are automatically converted to LaTeX line breaks (\\) inside the \text{} wrapper.

  • Literal Escapes: Escaped LaTeX literals (e.g., \$, \%, \#) are safely passed into the \text{} block without triggering math modes. The escape character for \$ is automatically resolved for MicroTex compatibility.

Examples

# "mixed" mode (default) safely wraps text and preserves inline math
latex_wrap(r"(The equation \(E=mc^2\) is famous)")
#> [1] "\\text{The equation }E=mc^2\\text{ is famous}"

# "mixed" mode handles user-escaped characters seamlessly
latex_wrap(r"(Cost: \$100 for $x$ items)")
#> [1] "\\text{Cost: \\$100 for }x\\text{ items}"

# "mixed" mode converts R newlines to stacked text blocks
latex_wrap(r"(Line 1\nLine 2)")
#> [1] "\\text{Line 1\\nLine 2}"

# "math" mode returns the string completely unmodified
latex_wrap(r"(\frac{\alpha}{\beta})", input_mode = "math")
#> [1] "\\frac{\\alpha}{\\beta}"