This function is similar to knit_child() but is used in R
scripts instead. When the main R script is not called via
spin(), this function simply executes the child script via
sys.source(), otherwise it calls spin() to spin
the child script into a source document, and uses knit_child()
to compile it. You can call this function in R code, or using the syntax of
inline R expressions in spin() (e.g.
{{knitr::spin_child('script.R')}}).
spin_child(input, format)Filename of the input R script.
Passed to format in spin(). If not
provided, it will be guessed from the current knitting process.
A character string of the knitted R script.