Second attempt at organizing jsonpath operators and methods

Second attempt at 283a95da92.  Since we can't reorder the enum values
of JsonPathItemType, instead reorder the switch cases where they are
used to generally follow the order of the enum values, for better
maintainability.

src/backend/utils/adt/jsonpath.c

@@ -519,18 +519,9 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 		case jpiNull:
 			appendStringInfoString(buf, "null");
 			break;
-		case jpiKey:
-			if (inKey)
-				appendStringInfoChar(buf, '.');
-			escape_json(buf, jspGetString(v, NULL));
-			break;
 		case jpiString:
 			escape_json(buf, jspGetString(v, NULL));
 			break;
-		case jpiVariable:
-			appendStringInfoChar(buf, '$');
-			escape_json(buf, jspGetString(v, NULL));
-			break;
 		case jpiNumeric:
 			if (jspHasNext(v))
 				appendStringInfoChar(buf, '(');
@@ -576,58 +567,6 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			if (printBracketes)
 				appendStringInfoChar(buf, ')');
 			break;
-		case jpiLikeRegex:
-			if (printBracketes)
-				appendStringInfoChar(buf, '(');
-
-			jspInitByBuffer(&elem, v->base, v->content.like_regex.expr);
-			printJsonPathItem(buf, &elem, false,
-							  operationPriority(elem.type) <=
-							  operationPriority(v->type));
-
-			appendStringInfoString(buf, " like_regex ");
-
-			escape_json(buf, v->content.like_regex.pattern);
-
-			if (v->content.like_regex.flags)
-			{
-				appendStringInfoString(buf, " flag \"");
-
-				if (v->content.like_regex.flags & JSP_REGEX_ICASE)
-					appendStringInfoChar(buf, 'i');
-				if (v->content.like_regex.flags & JSP_REGEX_DOTALL)
-					appendStringInfoChar(buf, 's');
-				if (v->content.like_regex.flags & JSP_REGEX_MLINE)
-					appendStringInfoChar(buf, 'm');
-				if (v->content.like_regex.flags & JSP_REGEX_WSPACE)
-					appendStringInfoChar(buf, 'x');
-				if (v->content.like_regex.flags & JSP_REGEX_QUOTE)
-					appendStringInfoChar(buf, 'q');
-
-				appendStringInfoChar(buf, '"');
-			}
-
-			if (printBracketes)
-				appendStringInfoChar(buf, ')');
-			break;
-		case jpiPlus:
-		case jpiMinus:
-			if (printBracketes)
-				appendStringInfoChar(buf, '(');
-			appendStringInfoChar(buf, v->type == jpiPlus ? '+' : '-');
-			jspGetArg(v, &elem);
-			printJsonPathItem(buf, &elem, false,
-							  operationPriority(elem.type) <=
-							  operationPriority(v->type));
-			if (printBracketes)
-				appendStringInfoChar(buf, ')');
-			break;
-		case jpiFilter:
-			appendStringInfoString(buf, "?(");
-			jspGetArg(v, &elem);
-			printJsonPathItem(buf, &elem, false, false);
-			appendStringInfoChar(buf, ')');
-			break;
 		case jpiNot:
 			appendStringInfoString(buf, "!(");
 			jspGetArg(v, &elem);
@@ -640,22 +579,17 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 			printJsonPathItem(buf, &elem, false, false);
 			appendStringInfoString(buf, ") is unknown");
 			break;
-		case jpiExists:
-			appendStringInfoString(buf, "exists (");
+		case jpiPlus:
+		case jpiMinus:
+			if (printBracketes)
+				appendStringInfoChar(buf, '(');
+			appendStringInfoChar(buf, v->type == jpiPlus ? '+' : '-');
 			jspGetArg(v, &elem);
-			printJsonPathItem(buf, &elem, false, false);
-			appendStringInfoChar(buf, ')');
-			break;
-		case jpiCurrent:
-			Assert(!inKey);
-			appendStringInfoChar(buf, '@');
-			break;
-		case jpiRoot:
-			Assert(!inKey);
-			appendStringInfoChar(buf, '$');
-			break;
-		case jpiLast:
-			appendStringInfoString(buf, "last");
+			printJsonPathItem(buf, &elem, false,
+							  operationPriority(elem.type) <=
+							  operationPriority(v->type));
+			if (printBracketes)
+				appendStringInfoChar(buf, ')');
 			break;
 		case jpiAnyArray:
 			appendStringInfoString(buf, "[*]");
@@ -712,6 +646,35 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 								 v->content.anybounds.first,
 								 v->content.anybounds.last);
 			break;
+		case jpiKey:
+			if (inKey)
+				appendStringInfoChar(buf, '.');
+			escape_json(buf, jspGetString(v, NULL));
+			break;
+		case jpiCurrent:
+			Assert(!inKey);
+			appendStringInfoChar(buf, '@');
+			break;
+		case jpiRoot:
+			Assert(!inKey);
+			appendStringInfoChar(buf, '$');
+			break;
+		case jpiVariable:
+			appendStringInfoChar(buf, '$');
+			escape_json(buf, jspGetString(v, NULL));
+			break;
+		case jpiFilter:
+			appendStringInfoString(buf, "?(");
+			jspGetArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
+		case jpiExists:
+			appendStringInfoString(buf, "exists (");
+			jspGetArg(v, &elem);
+			printJsonPathItem(buf, &elem, false, false);
+			appendStringInfoChar(buf, ')');
+			break;
 		case jpiType:
 			appendStringInfoString(buf, ".type()");
 			break;
@@ -742,6 +705,43 @@ printJsonPathItem(StringInfo buf, JsonPathItem *v, bool inKey,
 		case jpiKeyValue:
 			appendStringInfoString(buf, ".keyvalue()");
 			break;
+		case jpiLast:
+			appendStringInfoString(buf, "last");
+			break;
+		case jpiLikeRegex:
+			if (printBracketes)
+				appendStringInfoChar(buf, '(');
+
+			jspInitByBuffer(&elem, v->base, v->content.like_regex.expr);
+			printJsonPathItem(buf, &elem, false,
+							  operationPriority(elem.type) <=
+							  operationPriority(v->type));
+
+			appendStringInfoString(buf, " like_regex ");
+
+			escape_json(buf, v->content.like_regex.pattern);
+
+			if (v->content.like_regex.flags)
+			{
+				appendStringInfoString(buf, " flag \"");
+
+				if (v->content.like_regex.flags & JSP_REGEX_ICASE)
+					appendStringInfoChar(buf, 'i');
+				if (v->content.like_regex.flags & JSP_REGEX_DOTALL)
+					appendStringInfoChar(buf, 's');
+				if (v->content.like_regex.flags & JSP_REGEX_MLINE)
+					appendStringInfoChar(buf, 'm');
+				if (v->content.like_regex.flags & JSP_REGEX_WSPACE)
+					appendStringInfoChar(buf, 'x');
+				if (v->content.like_regex.flags & JSP_REGEX_QUOTE)
+					appendStringInfoChar(buf, 'q');
+
+				appendStringInfoChar(buf, '"');
+			}
+
+			if (printBracketes)
+				appendStringInfoChar(buf, ')');
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -771,11 +771,11 @@ jspOperationName(JsonPathItemType type)
 			return "<=";
 		case jpiGreaterOrEqual:
 			return ">=";
-		case jpiPlus:
 		case jpiAdd:
+		case jpiPlus:
 			return "+";
-		case jpiMinus:
 		case jpiSub:
+		case jpiMinus:
 			return "-";
 		case jpiMul:
 			return "*";
@@ -783,26 +783,26 @@ jspOperationName(JsonPathItemType type)
 			return "/";
 		case jpiMod:
 			return "%";
-		case jpiStartsWith:
-			return "starts with";
-		case jpiLikeRegex:
-			return "like_regex";
 		case jpiType:
 			return "type";
 		case jpiSize:
 			return "size";
-		case jpiKeyValue:
-			return "keyvalue";
-		case jpiDouble:
-			return "double";
 		case jpiAbs:
 			return "abs";
 		case jpiFloor:
 			return "floor";
 		case jpiCeiling:
 			return "ceiling";
+		case jpiDouble:
+			return "double";
 		case jpiDatetime:
 			return "datetime";
+		case jpiKeyValue:
+			return "keyvalue";
+		case jpiStartsWith:
+			return "starts with";
+		case jpiLikeRegex:
+			return "like_regex";
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", type);
 			return NULL;
@@ -900,8 +900,8 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 		case jpiKeyValue:
 		case jpiLast:
 			break;
-		case jpiKey:
 		case jpiString:
+		case jpiKey:
 		case jpiVariable:
 			read_int32(v->content.value.datalen, base, pos);
 			/* FALLTHROUGH */
@@ -911,30 +911,24 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 			break;
 		case jpiAnd:
 		case jpiOr:
-		case jpiAdd:
-		case jpiSub:
-		case jpiMul:
-		case jpiDiv:
-		case jpiMod:
 		case jpiEqual:
 		case jpiNotEqual:
 		case jpiLess:
 		case jpiGreater:
 		case jpiLessOrEqual:
 		case jpiGreaterOrEqual:
+		case jpiAdd:
+		case jpiSub:
+		case jpiMul:
+		case jpiDiv:
+		case jpiMod:
 		case jpiStartsWith:
 			read_int32(v->content.args.left, base, pos);
 			read_int32(v->content.args.right, base, pos);
 			break;
-		case jpiLikeRegex:
-			read_int32(v->content.like_regex.flags, base, pos);
-			read_int32(v->content.like_regex.expr, base, pos);
-			read_int32(v->content.like_regex.patternlen, base, pos);
-			v->content.like_regex.pattern = base + pos;
-			break;
 		case jpiNot:
-		case jpiExists:
 		case jpiIsUnknown:
+		case jpiExists:
 		case jpiPlus:
 		case jpiMinus:
 		case jpiFilter:
@@ -950,6 +944,12 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 			read_int32(v->content.anybounds.first, base, pos);
 			read_int32(v->content.anybounds.last, base, pos);
 			break;
+		case jpiLikeRegex:
+			read_int32(v->content.like_regex.flags, base, pos);
+			read_int32(v->content.like_regex.expr, base, pos);
+			read_int32(v->content.like_regex.patternlen, base, pos);
+			v->content.like_regex.pattern = base + pos;
+			break;
 		default:
 			elog(ERROR, "unrecognized jsonpath item type: %d", v->type);
 	}
@@ -958,12 +958,12 @@ jspInitByBuffer(JsonPathItem *v, char *base, int32 pos)
 void
 jspGetArg(JsonPathItem *v, JsonPathItem *a)
 {
-	Assert(v->type == jpiFilter ||
-		   v->type == jpiNot ||
+	Assert(v->type == jpiNot ||
 		   v->type == jpiIsUnknown ||
-		   v->type == jpiExists ||
 		   v->type == jpiPlus ||
 		   v->type == jpiMinus ||
+		   v->type == jpiFilter ||
+		   v->type == jpiExists ||
 		   v->type == jpiDatetime);
 
 	jspInitByBuffer(a, v->base, v->content.arg);
@@ -974,21 +974,20 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 {
 	if (jspHasNext(v))
 	{
-		Assert(v->type == jpiString ||
+		Assert(v->type == jpiNull ||
+			   v->type == jpiString ||
 			   v->type == jpiNumeric ||
 			   v->type == jpiBool ||
-			   v->type == jpiNull ||
-			   v->type == jpiKey ||
-			   v->type == jpiAny ||
-			   v->type == jpiAnyArray ||
-			   v->type == jpiAnyKey ||
-			   v->type == jpiIndexArray ||
-			   v->type == jpiFilter ||
-			   v->type == jpiCurrent ||
-			   v->type == jpiExists ||
-			   v->type == jpiRoot ||
-			   v->type == jpiVariable ||
-			   v->type == jpiLast ||
+			   v->type == jpiAnd ||
+			   v->type == jpiOr ||
+			   v->type == jpiNot ||
+			   v->type == jpiIsUnknown ||
+			   v->type == jpiEqual ||
+			   v->type == jpiNotEqual ||
+			   v->type == jpiLess ||
+			   v->type == jpiGreater ||
+			   v->type == jpiLessOrEqual ||
+			   v->type == jpiGreaterOrEqual ||
 			   v->type == jpiAdd ||
 			   v->type == jpiSub ||
 			   v->type == jpiMul ||
@@ -996,16 +995,16 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiMod ||
 			   v->type == jpiPlus ||
 			   v->type == jpiMinus ||
-			   v->type == jpiEqual ||
-			   v->type == jpiNotEqual ||
-			   v->type == jpiGreater ||
-			   v->type == jpiGreaterOrEqual ||
-			   v->type == jpiLess ||
-			   v->type == jpiLessOrEqual ||
-			   v->type == jpiAnd ||
-			   v->type == jpiOr ||
-			   v->type == jpiNot ||
-			   v->type == jpiIsUnknown ||
+			   v->type == jpiAnyArray ||
+			   v->type == jpiAnyKey ||
+			   v->type == jpiIndexArray ||
+			   v->type == jpiAny ||
+			   v->type == jpiKey ||
+			   v->type == jpiCurrent ||
+			   v->type == jpiRoot ||
+			   v->type == jpiVariable ||
+			   v->type == jpiFilter ||
+			   v->type == jpiExists ||
 			   v->type == jpiType ||
 			   v->type == jpiSize ||
 			   v->type == jpiAbs ||
@@ -1014,6 +1013,7 @@ jspGetNext(JsonPathItem *v, JsonPathItem *a)
 			   v->type == jpiDouble ||
 			   v->type == jpiDatetime ||
 			   v->type == jpiKeyValue ||
+			   v->type == jpiLast ||
 			   v->type == jpiStartsWith ||
 			   v->type == jpiLikeRegex);