Release CHANGES IN knitr VERSION 0.8 · yihui/knitr

NEW FEATURES

output from other languages (e.g. python, awk, ...) can also be cached like R output when cache=TRUE; see 023-engine-python.Rmd for an example
added support for bash/shell scripts; use the chunk option engine='bash' or engine='sh' to write shell scripts in code chunks (#361)
a new function knit_rd() to knit package documentation (run examples code and insert output in the HTML documentation) (#227) (thanks, Taiyun Wei)
added LuaTeX support for tikz graphics with the tikzDevice package (set options(tikzDefaultEngine = 'luatex')); this feature requires tikzDevice version > 0.6.2 (#358) (thanks, Alastair Andrew)
a new chunk option fig.env to set which environment to use for figures in LaTeX, e.g. we can set fig.env='marginfigure' to use \begin{marginfigure} (#364) (thanks, Bryan Hanson)
added a new package option global.device (default FALSE) which specifies whether to use a global graphics device to capture plots; if TRUE, it is possible to write plot(1:10) in a previous chunk and abline(0, 1) in a latter chunk because all code chunks share the same device, however, this may also bring unexpected consequences (in particular, using par() can bring redundant plots)

dots in figure paths are more safely replaced with _ now, e.g. fig.path='../figure' will no longer be replaced by __/figure (#346) (thanks, @Ralfer)
the c() syntax for the chunk option dependson did not actually work, e.g. dependson=c('foo', 'bar') (#350) (thanks, Cassio Pereira)
fixed a bug when eval=FALSE and prompt=TRUE (the continuation character was used in some places where there should be the prompt character) (thanks, Derek Ogle)
persp() plots were not recognized in the last version (thanks, Jeffrey Racine)

leading spaces are allowed in chunk headers now, e.g. in the past <<>>= must appear in the beginning of a line, but now we can indent the chunk header by a number of white spaces; this amount of spaces will be stripped off the chunk if the whole chunk is indented (#236) (thanks, @jamiefolson and Vitalie Spinu)
markdown output will be indented if the original code chunk is indented; this allows chunk output to be nested within its parent environment, e.g. inside an ordered list (see 001-minimal.Rmd for example)
when the global chunk option eval=FALSE, inline R code will not be evaluated, and ?? is returned for inline R expressions (#367)

if getOption('OutDec') is not ., inline numeric output will be put inside \text{} in LaTeX to avoid situations like #348 (the normal math mode may add a space after the comma in 3,1415)
if the chunk option external==FALSE (default is TRUE), knitr will no longer automatically add \usepackage{tikz} to the LaTeX preamble; you need to add it manually (but it is recommended to use external=TRUE with cache=TRUE for the sake of speed, because compilation of tikz graphics may be slow)
*.brew generates *.txt by default (instead of *-out.brew)
knit(text = ...) will no longer write output in the console (the output is only returned as a character string)