Derive Macro MatchArg 

#[derive(MatchArg)]
{
    // Attributes available to this derive:
    #[match_arg]
}

Derive MatchArg: enables conversion between Rust enums and R character strings with match.arg semantics (partial matching, informative errors).

Usage

#[derive(Copy, Clone, MatchArg)]
enum Mode {
    Fast,
    Safe,
    Debug,
}

Attributes

• #[match_arg(rename = "name")] - Rename a variant’s choice string
• #[match_arg(rename_all = "snake_case")] - Rename all variants (snake_case, kebab-case, lower, upper)
• #[match_arg(alias = "name")] - Another spelling of a variant’s choice, matched when typed in full; the errors that list the choices name it after them ((or "name" for "choice"))
• #[match_arg(alias = "name", listed = false)] - The same, named by no error

Requirements

The enum must be Copy (MatchArg: Copy): derive Copy, Clone with it.

Generated Implementations

• MatchArg - Choice metadata and bidirectional conversion
• TryFromSexp - Convert R STRSXP/factor to enum (with partial matching)
• IntoR - Convert enum to R character scalar