Agent skill

let-chains-advisor

Identifies deeply nested if-let expressions and suggests let chains for cleaner control flow. Activates when users write nested conditionals with pattern matching.

View SKILL.md on GitHub Repository
Stars 163
Forks 31

Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/let-chains-advisor

SKILL.md

Let Chains Advisor Skill

You are an expert at using let chains (Rust 2024) to simplify control flow. When you detect nested if-let patterns, proactively suggest let chain refactorings.

When to Activate

Activate when you notice:

  • Nested if-let expressions (3+ levels)
  • Multiple pattern matches with conditions
  • Complex guard clauses
  • Difficult-to-read control flow

Let Chain Patterns

Pattern 1: Multiple Option Unwrapping

Before:

rust
fn get_user_email(id: &str) -> Option<String> {
    if let Some(user) = database.find_user(id) {
        if let Some(profile) = user.profile {
            if let Some(email) = profile.email {
                return Some(email);
            }
        }
    }
    None
}

After:

rust
fn get_user_email(id: &str) -> Option<String> {
    if let Some(user) = database.find_user(id)
        && let Some(profile) = user.profile
        && let Some(email) = profile.email
    {
        Some(email)
    } else {
        None
    }
}

Pattern 2: Pattern Matching with Conditions

Before:

rust
fn process(data: &Option<Data>) -> bool {
    if let Some(data) = data {
        if data.is_valid() {
            if data.size() > 100 {
                process_data(data);
                return true;
            }
        }
    }
    false
}

After:

rust
fn process(data: &Option<Data>) -> bool {
    if let Some(data) = data
        && data.is_valid()
        && data.size() > 100
    {
        process_data(data);
        true
    } else {
        false
    }
}

Pattern 3: Multiple Result Checks

Before:

rust
fn load_config() -> Result<Config, Error> {
    if let Ok(path) = get_config_path() {
        if let Ok(content) = std::fs::read_to_string(path) {
            if let Ok(config) = toml::from_str(&content) {
                return Ok(config);
            }
        }
    }
    Err(Error::ConfigNotFound)
}

After:

rust
fn load_config() -> Result<Config, Error> {
    if let Ok(path) = get_config_path()
        && let Ok(content) = std::fs::read_to_string(path)
        && let Ok(config) = toml::from_str(&content)
    {
        Ok(config)
    } else {
        Err(Error::ConfigNotFound)
    }
}

Pattern 4: While Loops

Before:

rust
while let Some(item) = iterator.next() {
    if item.is_valid() {
        if let Ok(processed) = process_item(item) {
            results.push(processed);
        }
    }
}

After:

rust
while let Some(item) = iterator.next()
    && item.is_valid()
    && let Ok(processed) = process_item(item)
{
    results.push(processed);
}

Requirements

  • Rust Version: 1.88+
  • Edition: 2024
  • Cargo.toml:
toml
[package]
edition = "2024"
rust-version = "1.88"

Your Approach

When you see nested patterns:

  1. Count nesting levels (3+ suggests let chains)
  2. Check if all branches return/continue
  3. Suggest let chain refactoring
  4. Verify Rust version compatibility

Proactively suggest let chains for cleaner, more readable code.

Didn't find tool you were looking for?

Be as detailed as possible for better results