[R] (not so real) function (more like #include)

[Gabor Grothendieck]

longfun could just pass a, b and d to each of the individual
functions and each of the individual functions could pass
out back as a return value.

f1 <- f2 <- function(a, b, d) a+b+d

longfun1 <- function() {
   a <- b <- d <- 1
   out <- f1(a, b, d)
   out <- f2(a, b, d) + out
   out
}

longfun1() # 6

If the problem is that a, b and d actually represent 100 variables, say,
and its a nuisance to pass them all explicitly you could do this:

f1 <- f2 <- function() with(parent.frame(), a + b + d)

longfun2 <- function() {
   a <- b <- d <- 1
   out <- f1()
   out <- f2() + out
   out
}

longfun2() # 6


or you could do it this way if you would prefer to have longfun
control the scoping rather than having it done within each
individual function:


f1 <- f2 <- function() a+b+d

longfun3 <- function() {
	a <- b <- d <- 1
	environment(f1) <- environment(f2) <- environment()
	out <- f1()
	f2() + out
}

longfun3() # 6


On 10/4/06, Meinhard Ploner <meinhardploner at gmx.net> wrote:
> Hello R users,
>
> I have a very long function with parts of that looking like a list of
> jobs. The first part of the function defines a lot of local
> variables, which are used by the jobs. Now I extracted the "job" part
> und putted them into an external file, used by "source(, local=T)",
> which is more comfortable to me. Apart from that it gives me the
> opportunity that more users can work on the project. Is it possible
> to define a function for that code and passing to it the environment
> of f() without save(list=ls()) and load() .... ?
>
> Thanks in advance
> Meinhard Ploner
>
> longfun <- f() {
>
>        ## lot of local variables:
>        a <- ...
>        b <- ...
>        d <- ...
>        ...
>
>        out <- ...
>
>        source("job1.txt", local=TRUE)   #changes out, uses a, b, d, ...
>
>        source("job2.txt", local=TRUE)  # changes out, uses a, b, d, ...
>        ...
> }
>
>
>
> version
>                _
> platform       i386-apple-darwin8.6.1
> arch           i386
> os             darwin8.6.1
> system         i386, darwin8.6.1
> status
> major          2
> minor          3.1
> year           2006
> month          06
> day            01
> svn rev        38247
> language       R
> version.string Version 2.3.1 (2006-06-01)
>
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