What documentation exists for R?

Chapter 7: R Miscellanea 84
computes the value 2 and returns it; the command
summary(glm(y~x+z, family=binomial))
fits a logistic regression model, computes some summary information and returns an object
of class "summary.glm" (see Section 8.1 [How should I write summary methods?], page 91).
If you type ‘1+1’ or ‘summary(glm(y~x+z, family=binomial))’ at the command line
the returned value is automatically printed (unless it is invisible()), but in other circumstances,
such as in a source()d file or inside a function it isn’t printed unless you
specifically print it.
To print the value use
print(1+1)
or
print(summary(glm(y~x+z, family=binomial)))
instead, or use source(file, echo=TRUE).
7.17 Why does outer() behave strangely with my function?
As the help for outer() indicates, it does not work on arbitrary functions the way the
apply() family does. It requires functions that are vectorized to work elementwise on
arrays. As you can see by looking at the code, outer(x, y, FUN) creates two large vectors
containing every possible combination of elements of x and y and then passes this to FUN
all at once. Your function probably cannot handle two large vectors as parameters.
If you have a function that cannot handle two vectors but can handle two scalars, then
you can still use outer() but you will need to wrap your function up first, to simulate
vectorized behavior. Suppose your function is
foo