Initial commit

skills/clap-patterns/templates/value-parser.rs

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+/// Value Parser Template with Custom Validation
+///
+/// This template demonstrates:
+/// - Custom value parsers
+/// - Range validation
+/// - Format validation (regex)
+/// - Error handling with helpful messages
+
+use clap::Parser;
+use std::ops::RangeInclusive;
+
+const PORT_RANGE: RangeInclusive<usize> = 1..=65535;
+
+/// Parse and validate port number
+fn port_in_range(s: &str) -> Result<u16, String> {
+    let port: usize = s
+        .parse()
+        .map_err(|_| format!("`{}` isn't a valid port number", s))?;
+
+    if PORT_RANGE.contains(&port) {
+        Ok(port as u16)
+    } else {
+        Err(format!(
+            "port not in range {}-{}",
+            PORT_RANGE.start(),
+            PORT_RANGE.end()
+        ))
+    }
+}
+
+/// Validate email format (basic validation)
+fn validate_email(s: &str) -> Result<String, String> {
+    if s.contains('@') && s.contains('.') && s.len() > 5 {
+        Ok(s.to_string())
+    } else {
+        Err(format!("`{}` is not a valid email address", s))
+    }
+}
+
+/// Parse percentage (0-100)
+fn parse_percentage(s: &str) -> Result<u8, String> {
+    let value: u8 = s
+        .parse()
+        .map_err(|_| format!("`{}` isn't a valid number", s))?;
+
+    if value <= 100 {
+        Ok(value)
+    } else {
+        Err("percentage must be between 0 and 100".to_string())
+    }
+}
+
+/// Validate directory exists
+fn validate_directory(s: &str) -> Result<std::path::PathBuf, String> {
+    let path = std::path::PathBuf::from(s);
+
+    if path.exists() && path.is_dir() {
+        Ok(path)
+    } else {
+        Err(format!("directory does not exist: {}", s))
+    }
+}
+
+#[derive(Parser)]
+#[command(name = "validator")]
+#[command(about = "CLI with custom value parsers and validation")]
+struct Cli {
+    /// Port number (1-65535)
+    #[arg(short, long, value_parser = port_in_range)]
+    port: u16,
+
+    /// Email address
+    #[arg(short, long, value_parser = validate_email)]
+    email: String,
+
+    /// Success threshold percentage (0-100)
+    #[arg(short, long, value_parser = parse_percentage, default_value = "80")]
+    threshold: u8,
+
+    /// Working directory (must exist)
+    #[arg(short, long, value_parser = validate_directory)]
+    workdir: Option<std::path::PathBuf>,
+
+    /// Number of retries (1-10)
+    #[arg(
+        short,
+        long,
+        default_value = "3",
+        value_parser = clap::value_parser!(u8).range(1..=10)
+    )]
+    retries: u8,
+}
+
+fn main() {
+    let cli = Cli::parse();
+
+    println!("Configuration:");
+    println!("  Port: {}", cli.port);
+    println!("  Email: {}", cli.email);
+    println!("  Threshold: {}%", cli.threshold);
+    println!("  Retries: {}", cli.retries);
+
+    if let Some(workdir) = cli.workdir {
+        println!("  Working directory: {}", workdir.display());
+    }
+
+    // Your application logic here
+    println!("\nValidation passed! All inputs are valid.");
+}