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Add a syntax highlighting grammar

Source: R/markdown-highlight.R
register_highlighter.Rd

Adds a language for highlighting fenced code blocks in markdown_box_grob(), from a KDE syntax file (the format used by Kate and Pandoc). The easiest start is a copy of a built-in grammar:

Usage

register_highlighter(lang, file)

Arguments

lang

Language name, as written after the opening fence. Case is ignored. A built-in language of the same name is replaced.

file

Path to a KDE syntax XML file.

Value

lang, invisibly.

Details


  file.copy(system.file("highlight", "python.xml",
                        package = "gridmicrotex"),
            "mylang.xml")

Many files from https://kate-editor.org/syntax/ work as they are. Files that use dynamic rules are refused with an error. Those files are mostly GPL or LGPL licensed; check the licence before you redistribute one.

Colours come from markdown_style(), using Pandoc's class names (kw keyword, co comment, st string, ...), so a grammar needs no colours of its own.

See also

available_highlighters, markdown_box_grob, markdown_style

Examples

# Registering a grammar under a name of your own.
f <- system.file("highlight", "python.xml", package = "gridmicrotex")
register_highlighter("mypython", f)
"mypython" %in% available_highlighters()
#> [1] TRUE