agentsqripts/lib/wet-code/ast/semantic-similarity/calculators/calculateStructureSimilarity.js

Comprehensive static code analysis toolkit for identifying technical debt, security vulnerabilities, performance issues, and code quality problems

/**
 * @file AST-based structural similarity calculator for syntactic pattern analysis
 * @description Single responsibility: Assess code block similarity through Abstract Syntax Tree node type comparison
 * 
 * This calculator evaluates similarity between code blocks by analyzing their AST node types,
 * providing fundamental structural similarity assessment based on syntactic patterns. AST-based
 * comparison enables detection of functionally equivalent code that might use different surface
 * syntax but share underlying structural patterns.
 * 
 * Design rationale:
 * - AST node type comparison provides syntax-agnostic structural similarity assessment
 * - Function type equivalence recognizes different function declaration styles as structurally similar
 * - High similarity for exact AST matches indicates strong structural equivalence
 * - Medium similarity for function type variations accommodates different declaration styles
 * - Conservative baseline similarity ensures meaningful assessment for diverse code patterns
 * 
 * Structural similarity methodology:
 * - Perfect AST node matches yield high similarity (0.9) indicating strong structural equivalence
 * - Function type equivalence provides medium similarity (0.7) for different function declaration styles
 * - ArrowFunctionExpression, FunctionDeclaration, and FunctionExpression treated as equivalent patterns
 * - Conservative baseline similarity (0.3) for structurally different node types
 * - Systematic classification enables consistent structural pattern recognition
 */

/**
 * Calculate structural similarity based on AST node types
 */
function calculateStructureSimilarity(block1, block2) {
  // If both have the same AST node type, high similarity
  if (block1.astNode === block2.astNode) return 0.9;
  
  // If both are functions (different types), medium similarity
  const functionTypes = ['FunctionDeclaration', 'FunctionExpression', 'ArrowFunctionExpression'];
  if (functionTypes.includes(block1.astNode) && functionTypes.includes(block2.astNode)) {
    return 0.7;
  }
  
  return 0.3;
}

module.exports = calculateStructureSimilarity;