How to edit R library source files in-place - r

This a follow-up to How to edit and debug R library sources. I'm wondering if there's an easy way to edit an R library source file and cause the edited file to be loaded by library without reinstalling the code. I'm asking this in the context of a library that I'm developing and am looking for an easy way to incrementally edit and test my code. I know about source and other ways of loading code into an R session, but I want to test scripts that do the usual library thing.
Thanks!

It sounds like you're developing a packages. If that's the case then using the devtools package is probably what you want to do. The load_all() function will systematically reload all of your code so you can make changes and test everything out.

Related

Link Project and R Version

I have two different versions of R installed, one which is up to date and which I use for all my regular R coding (needs to be up to date so that I can use various updated and new packages) and one which I use to access OLAP cubes (needs to be the R Client from Microsoft, because this is the only one which supports the olapR package, and which currently uses R version 3.4.3).
Since, in theory, I only have to access the OLAP cube once a month, I "outsourced" this task to a different RStudio project, in which I download and save the required data for all other projects. Hence, all other projects never require the olapR package to be installed and can and will be run in the up to date R version.
Now, ideally I would like to link my R version to my projects, so that I do not have to change my global R version and restart RStudio every time I access the OLAP cube or work on this data retrieval project (and then switch it back). However, I could not find any options in RStudio to achieve this result.
There are a few threads out there describing the same problem, but with no satisfactory answer in my opinion:
https://support.rstudio.com/hc/en-us/community/posts/200657296-Link-Project-and-R-Version
Rstudio project using different version of R
I also tried looking for a different package than olapR but with similar functionality, but could not find anything except X4R, which seems outdated and does not work for me (https://github.com/overcoil/X4R). Sadly, I am also unable to directly access the databases which the OLAP cube uses for its results, so I cannot go "around" it.
I am happy for any help or suggestions you can offer, whether it is a general workaround to link a project to a specific R version or the (less helpful for the community) solution of accessing the OLAP cube in a different way.
Thanks in advance!
Using the answer from MrGumble I created a .bat file that will execute my .R file using the desired R installation. Even though it is not the answer I thought I would get, I think it is an even better solution to the problem.
For all facing a similar issue, here is the .bat file (never created one before, so also had to google how to do it and I guess some might be in the same position):
#echo off
title Getting data for further processing in R
echo Retrieving OLAP data
echo.
"C:\Program Files\Microsoft\R Client\R_SERVER\bin\Rscript.exe" "C:\Users\me\Documents\Projects\!Data\script.R"
echo.
echo Saved data
echo.
pause
Thanks again to MrGumble for his help.
Skip RStudio.
RStudio is really just an editor (albeit powerful and useful) editor, which starts an R console for you (and the surrounding PATH variables, library locations, etc.).
If your monthly task only requires you to run the R-script (or a bit of interactive work), you can simply execute your preferred version of R from the command line and have it run your R script. E.g.
C:\Users\me>"C:\Program Files (x64)\Microsoft R\bin\Rscript" myscript.R
You might have to define some PATH variables so that the older R doesn't look for packages in the newer R's libraries, but that depends entirely on your current setup.

change functionality of R package

I am trying to get my head around an R package. I installed it from github, worked with it. Also downloaded the ZIP-File from github which contains the files of the package. For experimental reasons I added some code in the files I downloaded.
Now I would like to see whether my changes do what they are supposed to do.
Is there an easy way to do this?
I would like to avoid creating a whole new package and installing it.
Or is this the only way?
I had the idea to directly change the code in the package I installed (location received from the function path.package()). Unfortunately I cannot access the code there.
The tutorials I read were also not helpful.
I would be thankful for any advice.

How can I reinstall or recompile already installed packages in Julia?

Is it possible to reinstall or recompile an already installed package in Julia? I did not find any hints in the official documentation. whos() did not reveal anything useful either.
Best
As was pointed out in the answer below by #ivarne my question can also be understood as:
"How can I reload a package that has been loaded with import or using in a Julia session?"
This question has also been answered by #ivarne.
You can re-run the package build script with Pkg.build("pkgname"). The actual compiling of the packages is just in time so they are complied when you load them.
Not sure about the terminology you use, but if you think about reloading a package (with import or using), it is complicated and the best approach is to restart Julia.
A function called reload() exists, but it has some limitations. While developing a Package, you might consider using something like the Autoreload.jl package to make it easier to reload the files you are working on.
If you are developing package and heve it installed using dev command, than Base.compilecache(Base.PkgId(PDFIO)) does the job.
In this case PDFIO is the package that I'm working on.
It is more convenient than restarting julia.

Interfacing R with other non-Java languages / Compiling R to executable

I've developed a .R script that works with a DB, does a bunch of processing and outputs graphs and tables. I can output that data as comma-separated values and pictures, to later import them on my software, that I have no issue.
The problem is how can I distribute my application without having to make a complete install of R on the client. I've seen things like RJava, but my app is on VB6 (yeah...) and I don't see any libraries, or ways to compile to exe. The compile package only makes compiled versions of any function you define, like what psyco used to do for Python (before Pypy).
Does anyone have some insight on compiling R to avoid having the user to install an entire additional software?
EDIT: Does an R compiler exist? This question relates deeply to mine, but I haven't seen how it can be used to make a full script an exe. You can just compile a main function and cat it to a file? Is that even possible?
The short answer is "no, that will not work".
There simply is no compiler that allows you to shrink-wrap your app. So your best best may be either
using the headless Rserve over the network, or
using the R (D)COM server used by RExcel et al

How to edit and debug R library sources

I've included a library called blotter in my R script which has a bug in it. Is there an easy way for me to edit the source to try and debug the issue?
Look up the trace and browser functions, they are the basic tools in R for debugging. Say you want to edit the source of function foo, then saying
trace("foo",edit=TRUE)
will open up the source of foo in the editor for you to change. However, this is for interactive debugging; the source files in the packages are not changed. So once you have found the bug, you need to change the package source files for the change to be permanent.
Such a feature is implemented in the development version of R (Jul 16, 2010):
A new facility has been added to r-devel for experimenting by authors of
packages.
The idea is to insert modified code from the package source into the
running package without re-installing. So one can change, test, change,
etc in a quick loop.
The mechanism is to evaluate some files of source code, returning an
environment object which is a snapshot of the code. From this
environment, functions and methods can be inserted into the environment
of the package in the current session. The insertion uses the trace()
mechanism, so the original code can be restored.
The one-step version is:
insertSource("mySourceFile.R", package = "myPackage", functions = "foo")
See this post for further details: Inserting and testing revised functions in a package
Your question of Is there an easy way for me to edit the source to try and debug the issue? has the obvious answer: Use the source, Luke!
blotter is a package on R-Forge from where you can get blotter sources here. That is the standard way of looking at Open Source and possibly helping it along with a bug fix.

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