Crate path_macro2 

path_macro2

A cross-platform path construction macro for Rust that provides an intuitive syntax for building file paths while automatically handling platform-specific path separators.

Features

• Dual syntax support: Use either slash (/) or comma (,) separators
• Cross-platform: Automatically uses correct path separators (\ on Windows, / on Unix-like systems)
• Variable interpolation: Support for runtime variables and expressions
• Multiple segment types: Identifiers, dotted names, string literals, and expressions
• Zero dependencies: Lightweight macro-only implementation

Installation

Add this to your Cargo.toml:

[dependencies]
path_macro2 = "0.1.1"

Usage

Basic Syntax

The macro supports two equivalent syntaxes:

use path_macro2::path;

// Slash syntax
let path1 = path!(vendor / dll / windivert.c);

// Comma syntax  
let path2 = path!(vendor, dll, windivert.c);

// Both produce the same result:
// Windows: "vendor\dll\windivert.c"
// Unix:    "vendor/dll/windivert.c"

Supported Segment Types

Identifiers and Dotted Names

let path = path!(vendor / include);           // Simple identifiers
let file = path!(config / settings.json);    // Dotted identifiers

String Literals (for spaces and special characters)

let path = path!("my folder" / "sub folder" / file.txt);
let docs = path!("Program Files" / "MyApp" / readme.md);

Variable Interpolation

let base = "vendor";
let version = "1.0";

// Variables wrapped in curly braces
let path = path!({base} / dll / file.txt);
let versioned = path!(libs / {format!("v{}", version)} / library.so);

Platform-Specific Examples

Unix/Linux Absolute Paths

let abs_path = path!("/" / "usr" / "local" / "bin" / "myapp");
// Result: "/usr/local/bin/myapp"

Windows Paths

// Drive letter paths
let win_path = path!("C:\\" / "Program Files" / "MyApp" / "app.exe");
// Result: "C:\Program Files\MyApp\app.exe"

// UNC network paths
let unc_path = path!("\\\\" / "server" / "share" / "file.txt");
// Result: "\\server\share\file.txt"

Complex Examples

use path_macro2::path;

fn main() {
    let project_root = std::env::var("PROJECT_ROOT").unwrap_or_else(|_| ".".to_string());
    let build_type = "release";
    
    // Mixed usage with variables and literals
    let output_path = path!({project_root} / "target" / {build_type} / "myapp.exe");
    
    // Handling paths with spaces
    let data_path = path!({project_root} / "test data" / "sample files" / input.csv);
    
    // Cross-platform configuration
    let config_path = if cfg!(windows) {
        path!("C:\\" / "ProgramData" / "MyApp" / config.toml)
    } else {
        path!("/" / "etc" / "myapp" / config.toml)
    };
    
    println!("Output: {}", output_path.display());
    println!("Data: {}", data_path.display());
    println!("Config: {}", config_path.display());
}

How It Works

The path! macro processes path segments and automatically:

1. Converts identifiers to strings: vendor becomes "vendor"
2. Handles dotted identifiers: file.txt becomes "file.txt"
3. Preserves string literals: "my folder" stays as-is
4. Evaluates expressions: {base_path} evaluates the variable
5. Builds PathBuf: Uses std::path::PathBuf::push() for proper platform handling

The result is always a std::path::PathBuf that uses the correct path separators for the target platform.

Comparison with Alternatives

Method	Cross-platform	Readable	Variables	Compile-time
path_macro2::path!	✅	✅	✅	✅
std::path::Path::join()	✅	❌	✅	❌
String concatenation	❌	❌	✅	❌
format!() with /	❌	⚠️	✅	❌

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Macros

path

Cross-platform path construction macro.