The cacheSweave Package

The Sweave system of Leisch (2002) is a literate programming tool based on ideas of Knuth (1984) and is currently part of the core R installation. Specifically, Sweave is a system for processing documents that mix LTEX document formatting with R code. R code can be interspersed within the LTEX markup by indicating “code chunks”. These code chunks are evaluated by the Sweave function in R and the code is replaced with the results of the evaluation. For example, the code for fitting a linear model and summarizing the estimated regression coefficients might be replaced by a formatted table of estimated regression coefficients along with standard errors and p-values. Another possibility is for the code to replaced by a plot which shows the data and the fitted regression line. In either case, the author writes the code to generate the output and Sweave runs the code and places the output in the final document. Given a file written in the Noweb format (Ramsey, 1994), one can generate a LTEX file by running in R