Add Programming Paradigm Enforcement/Suggestions (Starting with Functional Programming)

Implement configurable programming paradigm checks and suggestions that can guide developers to write code following specific paradigms, with initial focus on functional programming.

Problem Statement

Currently, Sourcery focuses on general code quality improvements but doesn't provide paradigm-specific refactoring suggestions. Developers who want to follow specific programming paradigms (functional, object-oriented, etc.) have to manually identify and refactor code patterns, which can be time-consuming and inconsistent across teams.

Proposed Feature

Add a configuration option to enable paradigm-specific analysis and suggestions, starting with functional programming. This would include:

Functional Programming Checks:

• Detect and suggest replacing loops with map(), filter(), reduce()

• Identify iterative loops and suggest tail-recursive alternatives

• Flag non-tail recursive functions and suggest tail-recursive refactoring

• Identify mutable data structures and suggest immutable alternatives

• Flag side effects in functions and suggest pure function alternatives

• Recommend function composition over nested function calls

• Suggest replacing class-based solutions with function-based ones where appropriate

• Identify opportunities for currying and partial application

Example Transformations

Loop to Tail Recursion:

# Before - Iterative

def factorial(n):

    result = 1

    for i in range(1, n + 1):

        result *= i

    return result

def sum_list(lst):

    total = 0

    for item in lst:

        total += item

    return total

Sourcery Suggestion:

def factorial(n, acc=1):
    return acc if n <= 1 else factorial(n - 1, acc * n)

def sum_list(lst, acc=0):
    return acc if not lst else sum_list(lst[1:], acc + lst[0])

Benefits

• Consistency: Enforce coding standards across teams

• Learning: Help developers learn paradigm-specific patterns including recursion

• Performance: Tail recursion can be optimized by interpreters/compilers

• Code Quality: Improve maintainability through paradigm adherence

• Stack Safety: Promote tail recursion to avoid stack overflow issues

• Flexibility: Configurable per project needs

Future Extensions

• Object-Oriented Programming paradigm checks

• Procedural programming guidelines

• Custom paradigm definitions

• Team-specific paradigm rules

• Recursion depth analysis and optimization suggestions

Use Cases

• Educational: Teaching functional programming and recursion concepts

• Team Standards: Enforcing consistent coding paradigms

• Legacy Refactoring: Migrating codebases to different paradigms

• Code Reviews: Automated paradigm compliance checking

• Performance Optimization: Converting inefficient recursion to tail recursion

Technical Considerations

• Warn about Python's recursion limit (default 1000) when suggesting recursive solutions

• Provide options to use functools.lru_cache for memoization when appropriate

• Consider suggesting iterative approaches when recursion depth could be problematic

This feature would significantly enhance Sourcery's value for developers and teams who want to maintain consistent programming paradigms while leveraging automated refactoring suggestions, with special emphasis on proper recursive patterns.