R/md-inlines.R

In gluedown: Wrap Vectors in Markdown Formatting

#' Markdown code span
#'
#' Take a character vector and wrap each element in backticks to create a glue
#' vector of inline code spans. This inline is rendered as a `<code>` HTML tag.
#'
#' @details
#' A backtick string is a string of one or more backtick characters that is
#' neither preceded nor followed by a backtick.
#'
#' A code span begins with a backtick string and ends with a backtick string
#' of equal length. The contents of the code span are the characters between
#' the two backtick strings, normalized in the following ways: * First, line
#' endings are converted to spaces. * If the resulting string both begins and
#' ends with a space character, but does not consist entirely of space
#' characters, a single space character is removed from the front and back.
#' This allows you to include code that begins or ends with backtick
#' characters, which must be separated by whitespace from the opening or
#' closing backtick strings.
#' @param x The text to be formatted as fixed-width inline code.
#' @return A `glue` vector of length equal to `x`.
#' @family inline functions
#' @examples
#' md_code("ex_var")
#' md_code(state.name[1:3])
#' @importFrom glue glue
#' @export
md_code <- function(x) {
  if (any(grepl("`", x))) {
    glue::glue("`` {x} ``")
  } else {
    glue::glue("`{x}`")
  }
}

#' Markdown bold emphasis
#'
#' Take a character vector and wrap each element in double asterisks to create a
#' glue vector of bold emphasis text. This inline is rendered as the `<stong>`
#' HTML tag.
#'
#' @details
#' A double `**` or `__` can open or close emphasis... Emphasis begins with a
#' delimiter that can open emphasis and ends with a delimiter that can close
#' emphasis, and that uses the same character (`__` or `**`) as the opening
#' delimiter.
#' @param x The text to be emphasized in bold.
#' @return A `glue` vector of length equal to `x`.
#' @family inline functions
#' @examples
#' md_bold("Example")
#' md_bold(state.name)
#' @importFrom glue glue
#' @export
md_bold <- function(x) {
  glue::glue("**{x}**")
}

#' Markdown italic emphasis
#'
#' Take a character vector and wrap each element in single underscores to create
#' a glue vector of italic emphasis text. This inline is rendered as the `<em>`
#' HTML tag.
#'
#' @details
#' A single `*` or `_` can open or close emphasis... Emphasis begins with a
#' delimiter that can open emphasis and ends with a delimiter that can close
#' emphasis, and that uses the same character (`_` or `*`) as the opening
#' delimiter.
#' @param x The text to be emphasized in italics.
#' @return A `glue` vector of length equal to `x`.
#' @family inline functions
#' @examples
#' md_italic("Example")
#' md_italic(state.name)
#' @importFrom glue glue
#' @export
md_italic <- function(x) {
  glue::glue("_{x}_")
}

#' Markdown strikethrough (extension)
#'
#' Take a character vector and wrap each element in tildes to create a glue
#' vector of strikethrough text. This inline is rendered as the `<strike>` HTML
#' tag.
#'
#' @details
#' GFM enables the strikethrough extension, where an additional emphasis type is
#' available. Strikethrough text is any text wrapped in two tildes (`~`).
#' @param x A character vector of text to be striked through.
#' @return A `glue` vector of length equal to `x`.
#' @family inline functions
#' @family markdown extensions
#' @examples
#' md_strike("Example")
#' md_strike(state.name[1:3])
#' @importFrom glue glue
#' @export
md_strike <- function(x) {
  glue::glue("~~{x}~~")
}