extract_optional_LaTeX_argument: Extract optional argument
In TeXCheckR: Parses LaTeX Documents for Errors

Extract optional argument

extract_optional_LaTeX_argument(
  tex_lines,
  command_name,
  n = 1L,
  by.line = FALSE
)

`tex_lines`	A character vector reading from a LaTeX document.
`command_name`	Name of command (without backslash)
`n`	Which optional argument to extract.
`by.line`	Should the output be one row per command (`FALSE`, the default), with extracts concatenated via `paste0(..., collapse = "")` or one row per line per command?