Join Function Implementation

Purpose

Implement a join function for XMD that takes an array and returns a comma-separated string.

Current Issue

  • User wants to use join ["debug","for now","in real","in a real","mock"]
  • This function doesn’t exist in XMD system
  • Currently results in empty output

Requirements

  • Function name: join
  • Input: Array of strings
  • Output: Comma-separated string (e.g., “debug, for now, in real, in a real, mock”)
  • Follow XMD function calling conventions

Implementation Plan

  1. Create test first (test-driven development)
  2. Add join function to AST function evaluation system
  3. Handle array input and string output
  4. Use existing XMD function patterns

Technical Notes

  • Must integrate with existing AST function call system
  • Follow file/folder naming: ast_evaluate_function_join/ast_evaluate_function_join.c
  • Handle memory management properly
  • Return meaningful error codes
  • Support both array literals and array variables

Success Criteria

  • join ["a","b","c"] returns “a, b, c”
  • set arr = ["x","y"]; join arr works
  • Memory is properly managed
  • Error handling for invalid inputs