Revert SQL/JSON features

The reverts the following and makes some associated cleanups:

    commit f79b803dc: Common SQL/JSON clauses
    commit f4fb45d15: SQL/JSON constructors
    commit 5f0adec25: Make STRING an unreserved_keyword.
    commit 33a377608: IS JSON predicate
    commit 1a36bc9db: SQL/JSON query functions
    commit 606948b05: SQL JSON functions
    commit 49082c2cc: RETURNING clause for JSON() and JSON_SCALAR()
    commit 4e34747c8: JSON_TABLE
    commit fadb48b00: PLAN clauses for JSON_TABLE
    commit 2ef6f11b0: Reduce running time of jsonb_sqljson test
    commit 14d3f24fa: Further improve jsonb_sqljson parallel test
    commit a6baa4bad: Documentation for SQL/JSON features
    commit b46bcf7a4: Improve readability of SQL/JSON documentation.
    commit 112fdb352: Fix finalization for json_objectagg and friends
    commit fcdb35c32: Fix transformJsonBehavior
    commit 4cd8717af: Improve a couple of sql/json error messages
    commit f7a605f63: Small cleanups in SQL/JSON code
    commit 9c3d25e17: Fix JSON_OBJECTAGG uniquefying bug
    commit a79153b7a: Claim SQL standard compliance for SQL/JSON features
    commit a1e7616d6: Rework SQL/JSON documentation
    commit 8d9f9634e: Fix errors in copyfuncs/equalfuncs support for JSON node types.
    commit 3c633f32b: Only allow returning string types or bytea from json_serialize
    commit 67b26703b: expression eval: Fix EEOP_JSON_CONSTRUCTOR and EEOP_JSONEXPR size.

The release notes are also adjusted.

Backpatch to release 15.

Discussion: https://postgr.es/m/40d2c882-bcac-19a9-754d-4299e1d87ac7@postgresql.org

src/interfaces/ecpg/preproc/ecpg.trailer

@@ -467,7 +467,7 @@ type_declaration: S_TYPEDEF
 		/* an initializer specified */
 		initializer = 0;
 	}
-	var_type opt_pointer ECPGColLabel opt_array_bounds ';'
+	var_type opt_pointer ECPGColLabelCommon opt_array_bounds ';'
 	{
 		add_typedef($5, $6.index1, $6.index2, $3.type_enum, $3.type_dimension, $3.type_index, initializer, *$4 ? 1 : 0);
 
@@ -701,43 +701,6 @@ var_type:	simple_type
 				struct_member_list[struct_level] = ECPGstruct_member_dup(this->struct_member_list);
 			}
 		}
-		| STRING
-		{
-			/*
-			 * It's quite horrid that ECPGColLabelCommon excludes
-			 * unreserved_keyword, meaning that unreserved keywords can't be
-			 * used as type names in var_type.  However, this is hard to avoid
-			 * since what follows ecpgstart can be either a random SQL
-			 * statement or an ECPGVarDeclaration (beginning with var_type).
-			 * Pending a bright idea about how to fix that, we must
-			 * special-case STRING (and any other unreserved keywords that are
-			 * likely to be needed here).
-			 */
-			if (INFORMIX_MODE)
-			{
-				$$.type_enum = ECPGt_string;
-				$$.type_str = mm_strdup("char");
-				$$.type_dimension = mm_strdup("-1");
-				$$.type_index = mm_strdup("-1");
-				$$.type_sizeof = NULL;
-			}
-			else
-			{
-				/* this is for typedef'ed types */
-				struct typedefs *this = get_typedef("string");
-
-				$$.type_str = (this->type->type_enum == ECPGt_varchar || this->type->type_enum == ECPGt_bytea) ? EMPTY : mm_strdup(this->name);
-				$$.type_enum = this->type->type_enum;
-				$$.type_dimension = this->type->type_dimension;
-				$$.type_index = this->type->type_index;
-				if (this->type->type_sizeof && strlen(this->type->type_sizeof) != 0)
-					$$.type_sizeof = this->type->type_sizeof;
-				else
-					$$.type_sizeof = cat_str(3, mm_strdup("sizeof("), mm_strdup(this->name), mm_strdup(")"));
-
-				struct_member_list[struct_level] = ECPGstruct_member_dup(this->struct_member_list);
-			}
-		}
 		| s_struct_union_symbol
 		{
 			/* this is for named structs/unions */
@@ -1379,7 +1342,7 @@ ECPGTypedef: TYPE_P
 			/* an initializer specified */
 			initializer = 0;
 		}
-		ECPGColLabel IS var_type opt_array_bounds opt_reference
+		ECPGColLabelCommon IS var_type opt_array_bounds opt_reference
 		{
 			add_typedef($3, $6.index1, $6.index2, $5.type_enum, $5.type_dimension, $5.type_index, initializer, *$7 ? 1 : 0);
 

src/interfaces/ecpg/preproc/parse.pl

@@ -47,8 +47,6 @@ my %replace_string = (
 	'NOT_LA'         => 'not',
 	'NULLS_LA'       => 'nulls',
 	'WITH_LA'        => 'with',
-	'WITH_LA_UNIQUE' => 'with',
-	'WITHOUT_LA'     => 'without',
 	'TYPECAST'       => '::',
 	'DOT_DOT'        => '..',
 	'COLON_EQUALS'   => ':=',

src/interfaces/ecpg/preproc/parser.c

@@ -83,7 +83,6 @@ filtered_base_yylex(void)
 		case WITH:
 		case UIDENT:
 		case USCONST:
-		case WITHOUT:
 			break;
 		default:
 			return cur_token;
@@ -144,19 +143,6 @@ filtered_base_yylex(void)
 				case ORDINALITY:
 					cur_token = WITH_LA;
 					break;
-				case UNIQUE:
-					cur_token = WITH_LA_UNIQUE;
-					break;
-			}
-			break;
-
-		case WITHOUT:
-			/* Replace WITHOUT by WITHOUT_LA if it's followed by TIME */
-			switch (next_token)
-			{
-				case TIME:
-					cur_token = WITHOUT_LA;
-					break;
 			}
 			break;
 		case UIDENT: