[Rd] Trying to understand the search path and namespaces
murdoch.duncan at gmail.com
Tue Nov 16 02:43:44 CET 2010
Hadley Wickham wrote:
> Hi all,
> I'm trying to understand how the search path and namespaces interact.
> For example, take the devtools package which suggests the testthat
> package. Here's what the search path looks like after I load each of
> those packages:
Luke Tierney wrote up a nice description of this a few years ago. It's
either on developer.r-project.org, or in an old issue of R News.
>  ".GlobalEnv" "package:devtools" "package:stats"
>  "package:graphics" "package:grDevices" "package:utils"
>  "package:datasets" "package:methods" "Autoloads"
>  "package:base"
>  ".GlobalEnv" "package:testthat" "package:devtools"
>  "package:stats" "package:graphics" "package:grDevices"
>  "package:utils" "package:datasets" "package:methods"
>  "Autoloads" "package:base"
> My question is this: when I execute the test function in devtools
> function it calls the the test_package function in the testthat
> package - but that function is located higher up the search path - how
> does R find it?
> (I ask this question because I'm trying to simulate package loading
> from within R to simplify the development cycle, but something is
> missing in my knowledge of namespaces, and so I have the devel
> versions of my packages can't access packages that are loaded after
> they are)
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