the first version; closes yihui/knitr#327
roxygenize
the very first position should be 0 instead of 1, to calculate the correct number of spaces on the first line
a much cleaner solution to the case of line1 != line2
pass extra arguments to hilight() from hi_latex/hi_html
merge adjacent tokens of the same type
when an expression spans across multiple lines, the returned value is not necessarily of the same length as code
use hilight_one() to deal with prompt=TRUE
roxygenize
two vignettes: custom and internals
bump version