knitr include (not input) child

knitr-include-child.Rnw

This chunk below is from the child document.

<<set-parent, echo=FALSE, cache=FALSE>>=
if(!exists("master_mode")) master_mode <- F
if(!master_mode)
  knitr::set_parent('knitr-include.Rnw')
@

<<test-child, out.width='2in', fig.show='asis'>>=
1+1
rnorm(5)
plot(1)
boxplot(1:10)
str(mtcars)
@

knitr-include.Rnw

\documentclass{article}

\begin{document}

<<test-main>>=
options(width = 60)
summary(iris)
@

Let's see how to work with child documents in knitr. Below we include
the file \textsf{knitr-include-child.Rnw}:

<<child-demo, echo=FALSE, warning=FALSE>>=
master_mode <- T
knitr::knit("knitr-include-child.Rnw", "knitr-include-child.tex")
#cat("\\input{knitr-include-child}")# Add results='asis' to the chunk options
@
\input{knitr-include-child}
Done!

Modified from: http://yihui.name/knitr/demo/child/

\end{document}