CODEWITHSUNDEEP
r
user1424739
user1424739

Reputation: 13675

What is the purpose of `.Internal()`?

See the following. I don't understand what the purpose of .Internal is. Its documentation is not clear. Could anybody help me understand when .Internal is required and why it is needed?

R> f=file('f.R', 'r')
R> .Internal(parse(f, n = -1, NULL, '?', 'f.R', encoding='unknown'))
expression(f = function(x) {
    x
})
R> f=file('f.R', 'r')
R> parse(f, n = -1, NULL, '?', 'f.R', encoding='unknown')
expression(f = function(x) {
    x
})

To learn this better, I want to extract the C code from R base and compile it separately, then call .Internal on the compiled binary. Is there a way to do it?

Upvotes: 0

Views: 310

Answers (1)

user2554330
user2554330

Reputation: 44867

.Internal() is one of the interfaces to functions written in C within R. The other one is displayed as .Primitive(). You can read about the differences in Chapter 2 of the "R Internals" manual.

You shouldn't call .Internal() directly. It's there so that the R developers can write functions like parse() that do some things in R and some things in C. If you want to do that, you should be using .C(), .Call(), or .External(). (There's also .Fortran() with a Fortran interface.) These are described in the "Writing R Extensions" manual.

Upvotes: 3

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