rust / intermediate
Snippet
Struct Composition and Method Chaining Patterns
Struct composition with multiple constructors and chainable methods creates a clean API. The new() constructor provides simple initialization, while from_hex() offers validation with proper error handling using the ? operator. Method chaining is enabled by methods returning Self, allowing operations like lighten().to_hex(). The saturating_add prevents overflow when lightening colors.
snippet.rs
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struct Color {r: u8,g: u8,b: u8,}impl Color {fn new(r: u8, g: u8, b: u8) -> Self {Color { r, g, b }}fn from_hex(hex: &str) -> Result<Self, String> {let hex = hex.trim_start_matches('#');if hex.len() != 6 {return Err("Hex must be 6 characters".to_string());}let r = u8::from_str_radix(&hex[0..2], 16).map_err(|e| format!("Invalid red: {}", e))?;let g = u8::from_str_radix(&hex[2..4], 16).map_err(|e| format!("Invalid green: {}", e))?;let b = u8::from_str_radix(&hex[4..6], 16).map_err(|e| format!("Invalid blue: {}", e))?;Ok(Color { r, g, b })}fn lighten(&self, amount: u8) -> Self {Color {r: self.r.saturating_add(amount),g: self.g.saturating_add(amount),b: self.b.saturating_add(amount),}}fn to_hex(&self) -> String {format!("#{:02x}{:02x}{:02x}", self.r, self.g, self.b)}}fn main() {let red = Color::new(255, 0, 0);let light_red = red.lighten(50);let blue = Color::from_hex("#0000FF").expect("Invalid hex");let light_blue = blue.lighten(100);println!("{} -> {}", red.to_hex(), light_red.to_hex());println!("{} -> {}", blue.to_hex(), light_blue.to_hex());}
Breakdown
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fn from_hex(hex: &str) -> Result<Self, String> {
Alternative constructor with validation returns Result for error handling
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let r = u8::from_str_radix(&hex[0..2], 16)
Parses hex substring to u8 using base 16 radix
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.map_err(|e| format!("Invalid red: {}", e))?;
Converts parse error to user-friendly message and propagates
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self.r.saturating_add(amount)
Prevents overflow; caps at 255 instead of wrapping around