R: Spin goat's hair into wool

spin {knitr} | R Documentation

## Spin goat's hair into wool

### Description

This function takes a specially formatted R script and converts it to a literate programming document. By default normal text (documentation) should be written after the roxygen comment (`#'`) and code chunk options are written after `#+` or `#-` or `# ----`.

### Usage

    spin(hair, knit = TRUE, report = TRUE, text = NULL, envir = parent.frame(),
        format = c("Rmd", "Rnw", "Rhtml", "Rtex", "Rrst"), doc = "^#+'[ ]?",
        inline = "^[{][{](.+)[}][}][ ]*$", comment = c("^[# ]*/[*]", "^.*[*]/ *$"),
        precious = !knit && is.null(text))

### Arguments

`hair` | the path to the R script
`knit` | logical: whether to compile the document after conversion
`report` | logical: whether to generate report for ‘Rmd’, ‘Rnw’ and ‘Rtex’ output (ignored if `knit = FALSE`)
`text` | a character vector as an alternative way to `hair` to provide the R source; if `text` is not `NULL`, `hair` will be ignored
`envir` | the environment for `knit()` to evaluate the code
`format` | character: the output format (it takes five possible values); the default is R Markdown
`doc` | a regular expression to identify the documentation lines; by default it follows the roxygen convention, but it can be customized, e.g. if you want to use `##` to denote documentation, you can use `'^##\\s*'`
`inline` | a regular expression to identify inline R expressions; by default, code of the form `((code))` on its own line is treated as an inline expression
`comment` | a pair of regular expressions for the start and end delimiters of comments; the lines between a start and an end delimiter will be ignored; by default, the delimiters are `/*` in the beginning and `*/` in the end of a line (following the convention of C comments)
`precious` | logical: whether intermediate files (e.g., `.Rmd` files when `format` is `"Rmd"`) should be preserved; default `FALSE` if `knit == TRUE` and input is a file

### Details

Obviously the goat's hair is the original R script, and the wool is the literate programming document (ready to be knitted).

### Value

If `text` is `NULL`, the path of the final output document, otherwise the content of the output.

### Note

If the output format is Rnw and no document class is specified in roxygen comments, this function will automatically add the `article` class to the LaTeX document so that it is complete and can be compiled. You can always specify the document class and other LaTeX settings in roxygen comments manually.

When the output format is Rmd, it is compiled to HTML via `knit2html()`, which uses R Markdown v1 instead of v2. If you want to use the latter, you should call `rmarkdown::render()` instead.

### Author(s)

Yihui Xie, with the original idea from Richard FitzJohn (who named it as `sowsear()` which meant to make a silk purse out of a sow's ear)

### References

https://yihui.name/knitr/demo/stitch/

### See Also

`stitch` (feed a template with an R script)

### Examples

    #' write normal text like this and chunk options like below

    #+ label, opt=value

    # /*
    #' these lines are treated as comments in spin()
    1 + 1
    # */

    (s = system.file("examples", "knitr-spin.R", package = "knitr"))
    spin(s)  # default markdown
    o = spin(s, knit = FALSE)  # convert only; do not make a purse yet
    knit2html(o)  # compile to HTML

    # other formats
    spin(s, FALSE, format = "Rnw")  # you need to write documentclass after #'
    spin(s, FALSE, format = "Rhtml")
    spin(s, FALSE, format = "Rtex")
    spin(s, FALSE, format = "Rrst")

[Package knitr version 1.16 Index]