docs: add comprehensive NOTES.md documenting funcformat transformation challenges

- Document current 125/258 pass rate and funcformat analysis
- Identify key patterns: SQL syntax functions, aggregates in TypeCast, context exclusions
- Explain plateau at 124/258 and breakthrough with function-specific logic
- Include analysis scripts for investigating funcformat patterns
- Ready for systematic expansion based on failing test analysis

Co-Authored-By: Dan Lynch <[email protected]>

Author: devin-ai-integration[bot]

packages/transform/analyze_funcformat_patterns.js

@@ -0,0 +1,69 @@
+const { Parser } = require('@pgsql/parser');
+
+const testQueries = [
+  "SELECT TRIM(BOTH ' ' FROM '  hello  ')",
+  "SELECT SUBSTRING('hello' FROM 2 FOR 3)",
+  "SELECT POSITION('ll' IN 'hello')",
+  "SELECT OVERLAY('hello' PLACING 'XX' FROM 2 FOR 2)",
+  
+  "SELECT EXTRACT(YEAR FROM CURRENT_DATE)",
+  "SELECT DATE_PART('month', CURRENT_TIMESTAMP)",
+  "SELECT DATE_TRUNC('day', NOW())",
+  
+  "SELECT LENGTH('hello')",
+  "SELECT UPPER('hello')",
+  "SELECT LOWER('HELLO')",
+  "SELECT CONCAT('a', 'b')",
+  
+  "SELECT ABS(-5)",
+  "SELECT ROUND(3.14159, 2)",
+  "SELECT CEIL(3.14)",
+  "SELECT FLOOR(3.14)",
+  
+  "SELECT AVG(column1) FROM table1",
+  "SELECT SUM(column1) FROM table1",
+  "SELECT COUNT(*) FROM table1",
+  
+  "SELECT CAST(AVG(column1) AS NUMERIC(10,3)) FROM table1",
+  "SELECT CAST(SUM(column1) AS INTEGER) FROM table1"
+];
+
+console.log("Analyzing funcformat patterns between PG13 and PG14...\n");
+
+const parser13 = new Parser(13);
+const parser14 = new Parser(14);
+
+testQueries.forEach((sql, index) => {
+  console.log(`=== Query ${index + 1}: ${sql} ===`);
+  try {
+    const result13 = parser13.parse(sql);
+    const result14 = parser14.parse(sql);
+    
+    if (result13 && result14) {
+      const json13 = JSON.stringify(result13, null, 2);
+      const json14 = JSON.stringify(result14, null, 2);
+      
+      const funcformat13 = json13.match(/"funcformat":\s*"([^"]+)"/g) || [];
+      const funcformat14 = json14.match(/"funcformat":\s*"([^"]+)"/g) || [];
+      
+      console.log(`PG13 funcformat: ${funcformat13.join(', ') || 'none'}`);
+      console.log(`PG14 funcformat: ${funcformat14.join(', ') || 'none'}`);
+      
+      const funcnames13 = json13.match(/"str":\s*"([a-zA-Z_][a-zA-Z0-9_]*)"(?=.*"funcformat")/g) || [];
+      const funcnames14 = json14.match(/"str":\s*"([a-zA-Z_][a-zA-Z0-9_]*)"(?=.*"funcformat")/g) || [];
+      
+      if (funcnames14.length > 0) {
+        console.log(`Functions with funcformat in PG14: ${funcnames14.join(', ')}`);
+      }
+      
+      if (json13 !== json14) {
+        console.log("DIFFERENCE DETECTED!");
+      } else {
+        console.log("No differences found");
+      }
+    }
+  } catch (error) {
+    console.log("Parse error:", error.message);
+  }
+  console.log("---\n");
+});