relax (version 1.3.5)

tangleR: function to tangle a file

Description

tangleR reads a file that is written according to the rules of the noweb system and performs a specific kind of tangling. As a result a .R-file is generated.

Usage

tangleR(in.file, out.file, expand.roots = NULL,
expand.root.start = TRUE,insert.comments=TRUE,add.extension=TRUE)

Arguments

in.file

name of input file

out.file

name of output file; if missing the extension of the input file is turned to .R

expand.roots

name(s) of root(s) to be expanded; if NULL all will be processed

expand.root.start

if TRUE (default) root chunk "start" will be expanded

insert.comments

if TRUE comments with chunk inofs will be added to the code

add.extension

if TRUE output file name will get extension .R

Value

• usually a file with R code is generated

Details

General remarks: A noweb file consists of a mixture of text and code chunks. An @ character (in column 1 of a line) indicates the beginning of a text chunk. <>= (starting at column 1 of a line) is a header line of a code chunk with a name defined by the text between << and >>=. A code chunk is finished by the beginning of the next text chunk. Within the code chunk you can use other code chunks by referencing them by name ( for example by: <> ). In this way you can separate a big job in smaller ones.

Special remarks: tangleR expands code chunk start if flag expand.root.start is TRUE. Code chunks will be surrounded by comment lines showing the number of the code chunk the code is coming from. If you want to use << or >> in your code it may be necessary to escape them by an @-sign. Then you have to type in: @<< or @>>.

References

http://www.eecs.harvard.edu/~nr/noweb/intro.html

See Also

weaveR

Examples

## This example cannot be run by examples() but should be work 
## in an interactive R session
  tangleR("testfile.rev")
"tangleR("testfile.rev")"
## The function is currently defined as
function(in.file,out.file,expand.roots=NULL,expand.root.start=TRUE){
# german documentation of the code:
# look for file webR.pdf, P. Wolf 050204
...
  }