Add transforms feature

This provides a mechanism for specifying conversions between SQL data
types and procedural languages.  As examples, there are transforms
for hstore and ltree for PL/Perl and PL/Python.

reviews by Pavel Stěhule and Andres Freund

2 files changed, 32 insertions, 0 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 59c755d7a59..1685efe254b 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -3625,6 +3625,20 @@ _copyImportForeignSchemaStmt(const ImportForeignSchemaStmt *from)
 	return newnode;
 }
 
+static CreateTransformStmt *
+_copyCreateTransformStmt(const CreateTransformStmt *from)
+{
+	CreateTransformStmt *newnode = makeNode(CreateTransformStmt);
+
+	COPY_SCALAR_FIELD(replace);
+	COPY_NODE_FIELD(type_name);
+	COPY_STRING_FIELD(lang);
+	COPY_NODE_FIELD(fromsql);
+	COPY_NODE_FIELD(tosql);
+
+	return newnode;
+}
+
 static CreateTrigStmt *
 _copyCreateTrigStmt(const CreateTrigStmt *from)
 {
@@ -4568,6 +4582,9 @@ copyObject(const void *from)
 		case T_ImportForeignSchemaStmt:
 			retval = _copyImportForeignSchemaStmt(from);
 			break;
+		case T_CreateTransformStmt:
+			retval = _copyCreateTransformStmt(from);
+			break;
 		case T_CreateTrigStmt:
 			retval = _copyCreateTrigStmt(from);
 			break;
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 3bc81762af5..578ead54632 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1780,6 +1780,18 @@ _equalImportForeignSchemaStmt(const ImportForeignSchemaStmt *a, const ImportFore
 }
 
 static bool
+_equalCreateTransformStmt(const CreateTransformStmt *a, const CreateTransformStmt *b)
+{
+	COMPARE_SCALAR_FIELD(replace);
+	COMPARE_NODE_FIELD(type_name);
+	COMPARE_STRING_FIELD(lang);
+	COMPARE_NODE_FIELD(fromsql);
+	COMPARE_NODE_FIELD(tosql);
+
+	return true;
+}
+
+static bool
 _equalCreateTrigStmt(const CreateTrigStmt *a, const CreateTrigStmt *b)
 {
 	COMPARE_STRING_FIELD(trigname);
@@ -2991,6 +3003,9 @@ equal(const void *a, const void *b)
 		case T_ImportForeignSchemaStmt:
 			retval = _equalImportForeignSchemaStmt(a, b);
 			break;
+		case T_CreateTransformStmt:
+			retval = _equalCreateTransformStmt(a, b);
+			break;
 		case T_CreateTrigStmt:
 			retval = _equalCreateTrigStmt(a, b);
 			break;