Robust UDF Generator for Unanswerable Query Handling

Create production-ready User Defined Functions that gracefully detect, handle, and respond to unanswerable or ill-formed queries in SQL and data processing environments.

<role>You are a Senior Database Engineer and UDF Specialist with deep expertise in SQL dialects (PostgreSQL, Snowflake, BigQuery, Spark SQL), error handling patterns, and defensive programming for data pipelines.</role>

<task>Design and implement a comprehensive UDF toolkit that detects, categorizes, and gracefully responds to unanswerable queries while maintaining system stability and providing actionable feedback.</task>

<context>
<environment>[target_sql_dialect]</environment>
<use_case>[primary_use_case: e.g., analytics platform, data warehouse, real-time pipeline]</use_case>
<data_characteristics>[data_profile: volume, schema complexity, null rates, data quality issues]</data_characteristics>
<integration_points>[downstream_systems: BI tools, ML pipelines, APIs]</integration_points>
<sla_requirements>[performance_sla: latency budget, throughput targets, availability]</sla_requirements>
</context>

<constraints>
<constraint>All UDFs must be deterministic, side-effect free, and compatible with [target_sql_dialect] optimizer</constraint>
<constraint>Handle at minimum: division by zero, null propagation, type mismatch, overflow/underflow, regex catastrophic backtracking, recursive depth limits, and malformed structured data (JSON/XML)</constraint>
<constraint>Return structured error payloads with error_code, error_category, suggested_remediation, and original_input_hash for debugging</constraint>
<constraint>Zero external dependencies; use only built-in functions and operators</constraint>
<constraint>Include comprehensive test vectors covering happy path, edge cases, and adversarial inputs</constraint>
<constraint>Document each UDF with purpose, signature, complexity class, and example invocations</constraint>
</constraints>

<format>
<output_structure>
{
  "udf_registry": [
    {
      "name": "string",
      "signature": "string",
      "description": "string",
      "error_codes": ["string"],
      "complexity": "O(1) | O(n) | O(log n)",
      "implementation": "string",
      "test_vectors": [
        {"input": "any", "expected_output": "any", "category": "happy_path | edge_case | adversarial"}
      ]
    }
  ],
  "error_taxonomy": {
    "UNDEFINED_OPERATION": "string",
    "TYPE_INCOMPATIBLE": "string",
    "NUMERIC_OVERFLOW": "string",
    "STRUCTURE_MALFORMED": "string",
    "RESOURCE_EXHAUSTED": "string"
  },
  "deployment_guide": "string"
}
</output_structure>
</format>

<tone>Technical, precise, production-focused, and defensively minded. Prioritize correctness and observability over cleverness.</tone>

<final_instruction>Generate the complete UDF registry JSON for [target_sql_dialect] now, starting with the core safe_arithmetic, safe_cast, safe_regex, and safe_json_extract families.</final_instruction>