# R Internal Function Invocation

> Use when when you need to verify or retrieve package-internal metadata about compiled .NET assembly location and version before processing raw mass spectrometry files, or when testing the R↔C# dispatch mechanism in isolation without loading actual Orbitrap .raw data files.

- Skill: `holobiomicslab/r-internal-function-invocation` (Agent Skill)
- Install (CLI): `npx skillmds@latest add holobiomicslab/r-internal-function-invocation`
- Raw SKILL.md: https://api.skillmd.com/api/skills/holobiomicslab/r-internal-function-invocation/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- License: CC-BY-4.0
- Author: HolobiomicsLab (https://skillmd.com/u/holobiomicslab)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/holobiomicslab/r-internal-function-invocation

---


# R Internal Function Invocation

## Summary

Invoke unexported R package internal functions (prefixed with :::) to access low-level assembly dispatch and configuration metadata without requiring raw data file inputs. This skill enables direct querying of bundled .NET assembly paths and version information in the rawrr package's two-layer R/C# architecture.

## When to use

When you need to verify or retrieve package-internal metadata about compiled .NET assembly location and version before processing raw mass spectrometry files, or when testing the R↔C# dispatch mechanism in isolation without loading actual Orbitrap .raw data files.

## When NOT to use

- The rawrr package is not installed or not loaded in the R session.
- You need to read actual spectral or chromatographic data from .raw files (use exported functions like readSpectrum(), readChromatogram(), readFileHeader() instead).
- You are working with a different R proteomics package that does not use internal ::: functions for assembly dispatch.

## Inputs

- rawrr R package (loaded in R session)

## Outputs

- assembly directory path (character string pointing to .NET assembly location)
- assembly version string (character string with version metadata)

## How to apply

Use the ::: operator to call internal (non-exported) functions from the rawrr package: (1) invoke rawrr:::.rawrrAssembly() to retrieve the filesystem path to the precompiled .NET 8.0 assembly bundled with the package; (2) verify the returned path points to a valid directory containing the rawrr.exe executable; (3) invoke rawrr:::.getRawrrAssemblyVersion() to retrieve the version string of the .NET assembly; (4) verify a non-empty version string is returned. Both functions execute without requiring raw data file input, confirming successful internal dispatch between the R layer and managed C# layer. This demonstrates the two-layer architecture where R functions invoke compiled C# wrapper methods.

## Related tools

- **rawrr** (R package providing the internal functions .rawrrAssembly() and .getRawrrAssemblyVersion() for assembly path and version retrieval) — https://github.com/fgcz/rawrr
- **RawFileReader** (.NET assembly wrapped by rawrr; contains the compiled C# code invoked through the two-layer architecture) — https://github.com/thermofisherlsms/RawFileReader

## Examples

```
rawrr:::.rawrrAssembly(); rawrr:::.getRawrrAssemblyVersion()
```

## Evaluation signals

- rawrr:::.rawrrAssembly() returns a non-empty character string pointing to an existing filesystem directory.
- The returned assembly path contains a rawrr.exe executable file readable by the R process.
- rawrr:::.getRawrrAssemblyVersion() returns a non-empty version string matching semantic versioning format (e.g., '1.0.0').
- Both function calls execute without raising errors or warnings, indicating the R↔C# dispatch mechanism is functional.
- The returned assembly version string is consistent across repeated invocations in the same R session.

## Limitations

- Internal functions (:::) are not part of the public API and may change between package versions without deprecation warnings.
- On Windows systems, the decimal symbol must be configured as '.' for proper data extraction in downstream operations, though this affects the broader package rather than internal function invocation alone.
- These internal functions do not provide access to actual spectral or chromatographic data; they only return metadata about the assembly itself.

## Evidence

- [methods] R functions invoke compiled C# wrapper methods using a system call: "Specifically, `R` functions requesting access to data stored in binary raw files (reader family functions listed in Table 1) invoke compiled `C#` wrapper methods using a system call"
- [other] Assembly dispatch without raw data file input: "Can the rawrr package's internal assembly dispatch functions (rawrr:::.rawrrAssembly() and rawrr:::.getRawrrAssemblyVersion()) successfully retrieve the assembly path and version string without"
- [methods] Two-layer architecture with extracted information written to temporary storage: "In order to return extracted data back to the `R` layer we use file I/O. More specifically, the extracted information is written to a temporary location on the harddrive, read back into memory and"
- [readme] rawrr wraps RawFileReader .NET assembly functionality: "rawrr wraps the functionality of the [RawFileReader](https://github.com/thermofisherlsms/RawFileReader) [.NET assembly](https://www.mono-project.com/docs/advanced/assemblies-and-the-gac/)."