.R File Extension

Developers wrote R files to organize and manage the resources used by applications built for classic Mac OS and early versions of macOS. Rez processed these text declarations and produced compiled resource data that could be embedded in application bundles or other files.

The companion tool DeRez could reverse this process by converting compiled resources back into readable R files. Although modern versions of Apple Xcode no longer include these tools, they were once a standard part of older Mac development workflows.

You can open R files with any text editor, such as Apple TextEdit, Sublime Text, or Microsoft Visual Studio Code. Older versions of Apple Xcode included the Rez compiler, which developers used to compile R files into application resources.

Audio editing and digital audio workstation (DAW) applications create R files when users choose to work with split stereo audio rather than a single interleaved file. For example, Digital Performer, Cubase, and other multitrack editors may generate R files during export or when users record audio in a format that separates channels. This workflow can be useful for sound engineers who need separate control over each channel for mixing, effects processing, or correction.

NOTE: R files are usually saved in standard audio formats, such as .WAV or .AIFF, even though the extension .r indicates their channel role rather than their container format.

You can open R files with most DAWs, audio editors, and media players, including Avid Pro Tools, Audacity, and VideoLAN VLC Media Player (as long as the app supports the format in which the R file is saved). The apps will recognize it as a mono audio track. For full stereo playback, you must load both the R and corresponding L files and pair them within the audio software.

Developers use Ratfor to write code using constructs that FORTRAN does not natively support, such as C-style control flow statements, including if-else, switch, while, and for loops. This functionality makes it easier to write, read, and maintain complex programs while still generating valid FORTRAN code for execution. Developers working on scientific, engineering, or numerical computing projects often used Ratfor to simplify coding in older FORTRAN environments.

You can open R files with any plain text editor, such as Microsoft Notepad, Notepad++, or Microsoft Visual Studio Code, to view or edit the source code. To compile and run the code, you first process it with a Ratfor preprocessor to generate standard FORTRAN source code, which a FORTRAN compiler, such as gfortran or Intel Fortran Compiler, can then compile.

REBOL stands for "Relative Expression Based Object Language." The language is commonly used for creating Internet scripts and applications.