similarity-elixir

Elixir code similarity analyzer using Tree-sitter parser.

Installation

cargo install similarity-elixir

Usage

# Analyze a single Elixir file
similarity-elixir lib/my_module.ex

# Analyze multiple files
similarity-elixir lib/

# Set similarity threshold (default: 0.85)
similarity-elixir lib/ -t 0.9

# Show all functions
similarity-elixir lib/my_module.ex --show-functions

# Print similar function pairs with code
similarity-elixir lib/ -p

Options

• -t, --threshold <THRESHOLD> - Similarity threshold (0.0-1.0, default: 0.85)
• -p, --print - Print similar function pairs with source code
• --show-functions - Show all functions found
• --filter-function <NAME> - Filter results to functions containing NAME
• --filter-function-body <PATTERN> - Filter by function body content
• --min-lines <N> - Minimum function lines (default: 5)
• --rename-cost <COST> - Cost for renaming operations (default: 1.0)

Features

• Detects similar functions across Elixir modules
• Supports pattern matching and guard clauses
• Handles pipe operators and anonymous functions
• Recognizes module, protocol, and implementation definitions
• Fast AST-based comparison using Tree-sitter

Example

# Input: lib/calculator.ex
defmodule Calculator do
  def add(a, b) do
    a + b
  end

  def sum(x, y) do
    x + y
  end
end

$ similarity-elixir lib/calculator.ex
Analyzing Elixir code similarity...

Found 2 functions
  - add
  - sum

Duplicates in lib/calculator.ex:
------------------------------------------------------------
  lib/calculator.ex:2-4 add <-> lib/calculator.ex:6-8 sum
  Similarity: 100.00%

Algorithm

Uses Tree Structure Edit Distance (TSED) to compare function ASTs with configurable rename costs and size penalties.

License

MIT