Where to find package code

If a specific function is very large or has lots of documentation, it can make sense to give it its own file, named after the function. More often, a single. R file will contain multiple function definitions: such as a main function and its supporting helpers, a family of related functions, or some combination of the two.

Here are some examples from the actual source of the tidyr package at version 1. This is a common place to define small utilities that are used inside multiple package functions. R makes them easier to re-discover when you return to your package after a long break. The organisation of functions within files is less important in RStudio, which offers two ways to jump to the definition of a function:.

Keep typing to narrow the list and eventually pick a function or file to visit. This works for both functions and files in your project. With your cursor in a function name or with a function name selected, press F2. This works for functions defined in your package or in another package. Its format also allows it to be a more dynamic document than this book. There are many ways to apply styler to your code, depending on the context:.

When styler is installed, the RStudio Addins menu will offer several additional ways to style code:. The use of Git or another version control system is optional, but a recommended practice in the long-term. We explain its importance in The styler package can also be integrated with various platforms for hosting source code and doing continuous integration.

This allows maintainers to focus on reviewing the substance of the pull request, without having to nitpick small issues of whitespace or indentation 15 There are two main differences between code in scripts and packages:.

In a script, code is run … when you run it! However, we must, in order to appreciate that the code in a package is run when the package is built. This means your functions need to be thoughtful in the way that they interact with the outside world.

When you source a script, every line of code is executed and the results are immediately made available. Things are different with package code, because it is loaded in two steps. When you attach a package with library , these cached results are re-loaded and certain objects mostly functions are made available for your use. The full details on what it means for a package to be in binary form are given in 4.

You might think that this is what R CMD build does, but that actually makes a bundled package, a. For those who install packages from source, build time is essentially when they built and installed the package. If you put this in a script, x tells you when the script was source d.

But if you put that same code in a package, x tells you when the package binary was built. In section 6. Luckily, once you diagnose this problem, it is generally not difficult to fix. So dataTableDependency was an object defined in top-level package code and it depends on some paths obtained via system. As described in a GitHub issue ,. This works fine when the package is built and tested on the same machine.

However, if the package is built on one machine and then used on another as is the case with CRAN binary packages , then this will fail — the dependency will point to the wrong directory on the host. The heart of the solution is to make sure that system. Indeed, this fix was made here in commit db47 and in a few other packages that had similar code and a related check was added in htmlDependency itself.

This particular problem would now be caught by R CMD check , due to changes that came with staged installation as of R 3. In an early version, the function looked something like this:.

The problem was those objects were formed and cached when the binary package was built. The files are the source code. They contain the definitive listing of what is available in the package. This book makes a valiant effort to offer up-to-date information on almost every one of the most commonly used packages, but it never hurts to check the original. For example, I suggest that every time you install a new version of the database, you should check at a minimum the dbmsutil.

Where do you find all of this interesting code? If you are working in a UNIX environment, the files that define the built-in packages may be found in,. So if you are running Oracle 7. For example, the installation of a package without a language transform could install the English version of the application and the installation of the same package with a language transform could install the French version.

The transform is distinct from the. The English and French versions could have different product codes and the same package code because they are both installed with the same.

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