How to access the help/documentation .rd source files in R?

by

It seems you can extract the Rd sources from an installed R. I’m using R-devel (2011-09-05 r56942).

Get the database of Rd for the base package. 

library(tools)
db <- Rd_db("base")

Search for “grep.Rd” in the names of the Rd DB, for example: 

grep("grep.Rd", names(db), value = TRUE)
[1] "d:/murdoch/recent/R64/src/library/base/man/agrep.Rd"
[2] "d:/murdoch/recent/R64/src/library/base/man/grep.Rd"

Get just the Rd object for grep. 

db[grep("/grep.Rd", names(db))]
$`d:/murdoch/recent/R64/src/library/base/man/grep.Rd`
\title{Pattern Matching and Replacement}
\name{grep}
\alias{grep}
\alias{grepl}
\alias{sub}
\alias{gsub}
\alias{regexpr}
\alias{gregexpr}
\alias{regexec}
\keyword{character}
\keyword{utilities}
\description{
\code{grep}, \code{grepl}, \code{regexpr} and \code{gregexpr} search
for matches to argument \code{pattern} within each element of a
character vector: they differ in the format of and amount of detail in
the results.

\code{sub} and \code{gsub} perform replacement of the first and all
matches respectively.
}\usage{
...
...

There are tools for getting the components from the Rd objects, so you can refine searching to keywords or name, see examples in ?Rd_db and try this. 

lapply(db, tools:::.Rd_get_metadata, "name")

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