R: R Driver for Stangle

Rtangle {utils} | R Documentation

## R Driver for Stangle

### Description

A driver for `Stangle` that extracts R code chunks.

### Usage

    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

    ###################################################
    ### 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`

[Package utils version 2.15.1 Index]