knit_patterns {knitr}

Patterns to match and extract R code in a document

Description

Patterns are regular expressions and will be used in functions like base::grep() to extract R code and chunk options. The object knit_patterns controls the patterns currently used; see the references and examples for usage. All built-in patterns are available in the list all_patterns.

Usage

knit_patterns

Format

An object of class list of length 7.

References

Usage: https://yihui.org/knitr/objects/

Components in knit_patterns: https://yihui.org/knitr/patterns/

See Also

all_patterns

Examples

library(knitr)
opat = knit_patterns$get()  # old pattern list (to restore later)

apats = all_patterns  # a list of all built-in patterns
str(apats)
knit_patterns$set(apats[["rnw"]])  # set pattern list from apats

knit_patterns$get(c("chunk.begin", "chunk.end", "inline.code"))

# a customized pattern list; has to empty the original patterns first!
knit_patterns$restore()
# we may want to use this in an HTML document
knit_patterns$set(list(chunk.begin = "<!--helloR\\s+(.*)", chunk.end = "^byeR-->"))
str(knit_patterns$get())

knit_patterns$set(opat)  # put the old patterns back