refactor(format): subqueries and CTE lists on Doc-IR; fix CTE commas with trailing style

pkg/format/dml.go

@@ -338,7 +338,6 @@ func dmlSplitAndOr(toks []cst.Tok) [][]cst.Tok {
 // formatWithBody formats the body of a WITH clause by splitting CTE definitions
 // at depth-0 commas and formatting the subquery inside each AS (...) block.
 func formatWithBody(kwText string, body []cst.Tok, st config.Style) string {
-	nl := st.Newline
 
 	cteDefs := dmlSplitCommas(body)
 	// Filter spurious empty items.
@@ -357,37 +356,11 @@ func formatWithBody(kwText string, body []cst.Tok, st config.Style) string {
 		return kwText + " " + formatCTEDef(cteDefs[0], st)
 	default:
 		// Multiple CTEs: one per line with the configured comma style.
-		first := st.Indent + " "
-		cont := st.Indent + ","
-		contPad := strings.Repeat(" ", len(cont)) // same width as cont, no comma
-
-		var b strings.Builder
-		b.WriteString(kwText)
+		texts := make([]string, len(cteDefs))
 		for i, cteDef := range cteDefs {
-			b.WriteString(nl)
-
-			var headPfx, tailPfx string
-			if i == 0 || st.Commas != config.CommaLeading {
-				headPfx = first
-				tailPfx = first
-			} else {
-				headPfx = cont
-				tailPfx = contPad
-			}
-
-			cteText := formatCTEDef(cteDef, st)
-			cteLines := strings.Split(cteText, nl)
-			for j, line := range cteLines {
-				if j > 0 {
-					b.WriteString(nl)
-					b.WriteString(tailPfx)
-				} else {
-					b.WriteString(headPfx)
-				}
-				b.WriteString(line)
-			}
+			texts[i] = formatCTEDef(cteDef, st)
 		}
-		return b.String()
+		return dmlCommaList(kwText, texts, st)
 	}
 }
 
@@ -515,26 +488,21 @@ func dmlWrapSubquery(inner []cst.Tok, st config.Style) string {
 	if sub == "" {
 		return "()"
 	}
-	lines := strings.Split(sub, nl)
-
-	var b strings.Builder
-	b.WriteString("(")
-	for i, line := range lines {
-		if i == 0 && st.SubqueryContent != config.PlacementNewLine {
-			b.WriteString(line)
-			continue
+	// The first line stays on the "(" line unless subquery_content says
+	// new_line; every later line is indented one level.
+	var body []Doc
+	for i, line := range strings.Split(sub, nl) {
+		if i > 0 || st.SubqueryContent == config.PlacementNewLine {
+			body = append(body, HardLine())
 		}
-		b.WriteString(nl)
-		if line != "" {
-			b.WriteString(st.Indent)
-		}
-		b.WriteString(line)
+		body = append(body, Text(line))
 	}
+	doc := []Doc{Text("("), Indent(Concat(body...))}
 	if st.SubqueryClosing == config.PlacementNewLine {
-		b.WriteString(nl)
+		doc = append(doc, HardLine())
 	}
-	b.WriteString(")")
-	return b.String()
+	doc = append(doc, Text(")"))
+	return Render(Concat(doc...), 0, st.Indent, nl)
 }
 
 // litNL stands in for a newline inside a multi-line string literal while DML