1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/highlight.R
\name{hilight}
\alias{hilight}
\alias{hi_latex}
\alias{hi_html}
\title{Syntax highlight an R code fragment}
\usage{
hilight(code, format = c("latex", "html"), markup, prompt = FALSE, fallback = FALSE)
hi_latex(code, ...)
hi_html(code, ...)
}
\arguments{
\item{code}{a character string (the R source code)}
\item{format}{the output format}
\item{markup}{a data frame of two columns containing the markup commands}
\item{prompt}{whether to add prompts to the code}
\item{fallback}{whether to use the fallback method, i.e. the regular
expression based method; this method is not precise and only highlights a
few types of symbols such as comments, strings and functions;
\code{fallback} will be set to \code{TRUE} when the input \code{code} fails
to be \code{\link{parse}d}}
\item{...}{arguments to be passed to \code{hilight()}}
}
\value{
A character vector for the syntax highlighted code.
}
\description{
This function \code{\link{parse}}s the R code, fetches the tokens in it
(\code{\link{getParseData}}), and attach syntax highlighting commands onto
them. With proper style definitions for these commands (such as colors or
font styles), the R code will be syntax highlighted in the LaTeX/HTML output.
The two functions \code{hi_latex} and \code{hi_html} are wrappers of
\code{hilight} for LaTeX and HTML output, respectively.
}
\details{
For the \code{markup} data frame, the first column is put before the R
tokens, and the second column is behind; the row names of the data frame must
be the R token names; a special row is named \code{STANDARD}, which contains
the markup for the standard tokens (i.e. those that do not need to be
highlighted); if missing, the built-in data frames \code{highr:::cmd_latex}
and \code{highr:::cmd_html} will be used.
This function only binds markups onto R tokens, and the real syntax
highlighting must be done with style definitions, which is out of the scope
of this package. It was designed to be used as the syntax highlighting
infrastructure of other packages such as \pkg{knitr}, where the colors and
font styles are properly defined in the LaTeX preamble and HTML header.
}
\examples{
library(highr)
hilight("x=1 # assignment")
txt = c("a <- 1 # something", "c(y=\"world\", z=\"hello\")", "b=function(x=5) {",
"for(i in 1:10) {
if (i < x) print(i) else break}}", "z@child # S4 slot",
"'special chars <>#$\%&_{}'")
cat(hi_latex(txt), sep = "\\n")
cat(hi_html(txt), sep = "\\n")
# the markup data frames
highr:::cmd_latex
highr:::cmd_html
}
\seealso{
See the package vignettes \code{browseVignettes('highr')} for how
this function works internally.
}
\author{
Yihui Xie <\url{http://yihui.name}> and Yixuan Qiu
<\url{http://yixuan.cos.name}>
}
|
