Extract all YAML fragments from a file

These function extracts all YAML fragments from a file, returning a list of character vectors containing the extracted fragments.

extract_yaml_fragments(
  text,
  file,
  delimiterRegEx = "^---$",
  ignoreOddDelimiters = FALSE,
  encoding = "UTF-8",
  silent = TRUE
)

Arguments

text, file

As text or file, you can specify a file to read with encoding encoding, which will then be read using base::readLines(). If the argument is named text, whether it is the path to an existing file is checked first, and if it is, that file is read. If the argument is named file, and it does not point to an existing file, an error is produced (useful if calling from other functions). A text should be a character vector where every element is a line of the original source (like provided by base::readLines()); although if a character vector of one element and including at least one newline character (\\n) is provided as text, it is split at the newline characters using base::strsplit(). Basically, this behavior means that the first argument can be either a character vector or the path to a file; and if you're specifying a file and you want to be certain that an error is thrown if it doesn't exist, make sure to name it file.

delimiterRegEx

The regular expression used to locate YAML fragments.

ignoreOddDelimiters

Whether to throw an error (FALSE) or delete the last delimiter (TRUE) if an odd number of delimiters is encountered.

encoding

The encoding to use when calling readLines(). Set to NULL to let readLines() guess.

silent

Whether to be silent (TRUE) or informative (FALSE).

Value

A list of character vectors, where each vector corresponds to one YAML fragment in the source file or text.

Examples

extract_yaml_fragments(text="
---
First: YAML fragment
  id: firstFragment
---
Outside of YAML
---
Second: YAML fragment
  id: secondFragment
  parentId: firstFragment
---
Also outside of YAML
");
#> [[1]]
#> [1] "---"                  "First: YAML fragment" "  id: firstFragment" 
#> [4] "---"                 
#> attr(,"class")
#> [1] "yamlFragment"
#> 
#> [[2]]
#> [1] "---"                       "Second: YAML fragment"    
#> [3] "  id: secondFragment"      "  parentId: firstFragment"
#> [5] "---"                      
#> attr(,"class")
#> [1] "yamlFragment"
#> 
#> attr(,"class")
#> [1] "yamlFragments" "list"