R Driver for Stangle

Description

A driver for Stangle that extracts R code chunks.

Usage

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Rtangle()
RtangleSetup(file, syntax, output = NULL, annotate = TRUE,
             split = FALSE, quiet = FALSE, ...)

Arguments

file

Name of Sweave source file. See the description of the corresponding argument of Sweave.

syntax

An object of class SweaveSyntax.

output

Name of output file used unless split = TRUE: see ‘Details’.

annotate

By default, code chunks are separated by comment lines specifying the names and numbers of the code chunks. If FALSE the decorating comments are omitted.

split

Split output into a file for each code chunk?

quiet

If TRUE all progress messages are suppressed.

...

Additional named arguments setting defaults for further options.

Details

Unless split = TRUE, the default name of the output file is basename(file) with an extension corresponding to the Sweave syntax (e.g., ‘Rnw’, ‘Stex’) replaced by ‘R’. File names "stdout" and "stderr" are interpreted as the output and message connection respectively.

If splitting is selected (including by the options in the file), each chunk is written to a separate file with extension the name of the ‘engine’ (default ‘.R’).

The annotation is of one of the forms

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###################################################
### code chunk number 3: viewport
###################################################

###################################################
### code chunk number 18: grid.Rnw:647-648
###################################################

###################################################
### code chunk number 19: trellisdata (eval = FALSE)
###################################################

using either the chunk label or the file name and line numbers.

Note that this driver does not simple extract the code chunks verbatim because code chunks can re-use earlier chunks.

Supported Options

Rtangle supports the following options for code chunks (the values in parentheses show the default values):

engine:

character string ("R"). Only chunks with engine equal to "R" or "S" are processed.

keep.source:

logical (TRUE). If keep.source == TRUE the original source is copied to the file. Otherwise, deparsed source is output.

eval:

logical (TRUE). If FALSE, the code chunk is copied across but commented out.

prefix

Used if split = TRUE. See prefix.string.

prefix.string:

a character string, default is the name of the source file (without extension). Used if split = TRUE as the prefix for the filename if the chunk has no label, or if it has a label and prefix = TRUE. Note that this is used as part of filenames, so needs to be portable.

show.line.nos

logical (FALSE). Should the output be annotated with comments showing the line number of the first code line of the chunk?

Author(s)

Friedrich Leisch and R-core.

See Also

Sweave User Manual’, a vignette in the utils package.

Sweave, RweaveLatex

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