ABSTRACT
Besides knitr, there is a large number of tools for dynamic documents. Some are R packages, and others are tools in other languages such as Python and awk. This chapter discusses the overview of these tools with comparisons to knitr, and explains the differences between Sweave and knitr for Sweave users. It discusses the three packages based on Python for dynamic documents: Dexy, Python, and IPython. The knitr package was largely motivated by Sweave, which has been a longstanding prominent tool for dynamic documents in R, and is a part of base R. A lot of knitr's chunk options were borrowed from Sweave, such as eval, echo, results and so on, but the design is different, so there are several differences between them. By default, knitr uses a new type of syntax to parse chunk options, which is similar to R function arguments. This gives us much more power than the traditional Sweave syntax.
