Sweave {utils} | R Documentation

## Automatic Generation of Reports

### Description

`Sweave` provides a flexible framework for mixing text and S code for automatic report generation. The basic idea is to replace the S code with its output, such that the final document only contains the text and the output of the statistical anlysis.

### Usage

    Sweave(file, driver=RweaveLatex(), syntax=getOption("SweaveSyntax"), ...)
    Stangle(file, driver=Rtangle(), syntax=getOption("SweaveSyntax"), ...)

### Arguments

`file` | Name of Sweave source file.
`driver` | The actual workhorse, see details below.
`syntax` | An object of class `SweaveSyntax` or a character string with its name. The default installation provides `SweaveSyntaxNoweb` and `SweaveSyntaxLatex`.
`...` | Further arguments passed to the driver's setup function.

### Details

Automatic generation of reports by mixing word processing markup (like latex) and S code. The S code gets replaced by its output (text or graphs) in the final markup file. This allows to re-generate a report if the input data change and documents the code to reproduce the analysis in the same file that also produces the report.

`Sweave` combines the documentation and code chunks together (or their output) into a single document. `Stangle` extracts only the code from the Sweave file creating a valid S source file (that can be run using `source`). Code inside `\Sexpr{}` statements is ignored by `Stangle`.

`Stangle` is just a frontend to `Sweave` using a simple driver by default, which discards the documentation and concatenates all code chunks the current S engine understands.

### Hook Functions

Before each code chunk is evaluated, a number of hook functions can be executed. If `getOption("SweaveHooks")` is set, it is taken to be a collection of hook functions. For each logical option of a code chunk (`echo`, `print`, ...) a hook can be specified, which is executed if and only if the respective option is `TRUE`. Hooks must be named elements of the list returned by `getOption("SweaveHooks")` and be functions taking no arguments. E.g., if option `"SweaveHooks"` is defined as `list(fig = foo)`, and `foo` is a function, then it would be executed before the code in each figure chunk. This is especially useful to set defaults for the graphical parameters in a series of figure chunks.

Note that the user is free to define new Sweave options and associate arbitrary hooks with them. E.g., one could define a hook function for option `clean` that removes all objects in the global environment. Then all code chunks with `clean=TRUE` would start operating on an empty workspace.

### Syntax Definition

Sweave allows a very flexible syntax framework for marking documentation and text chunks. The default is a noweb-style syntax, as alternative a latex-style syntax can be used. See the user manual for details.

### Author(s)

Friedrich Leisch

### References

Friedrich Leisch: Sweave User Manual, 2002
http://www.ci.tuwien.ac.at/~leisch/Sweave

Friedrich Leisch: Dynamic generation of statistical reports using literate data analysis. In W. Härdle and B. Rönz, editors, Compstat 2002 - Proceedings in Computational Statistics, pages 575-580. Physika Verlag, Heidelberg, Germany, 2002. ISBN 3-7908-1517-9.

### See Also

`RweaveLatex`, `Rtangle`

### Examples

    testfile <- system.file("Sweave", "Sweave-test-1.Rnw", package = "utils")

    ## create a LaTeX file
    Sweave(testfile)

    ## create an S source file from the code chunks
    Stangle(testfile)
    ## which can be simply sourced
    source("Sweave-test-1.R")

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