Implement the DO statement to support execution of PL code without having

to create a function for it.

Procedural languages now have an additional entry point, namely a function
to execute an inline code block.  This seemed a better design than trying
to hide the transient-ness of the code from the PL.  As of this patch, only
plpgsql has an inline handler, but probably people will soon write handlers
for the other standard PLs.

In passing, remove the long-dead LANCOMPILER option of CREATE LANGUAGE.

Petr Jelinek

src/include/nodes/parsenodes.h

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.401 2009/08/02 22:14:53 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.402 2009/09/22 23:43:41 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1570,6 +1570,7 @@ typedef struct CreatePLangStmt
 	NodeTag		type;
 	char	   *plname;			/* PL name */
 	List	   *plhandler;		/* PL call handler function (qual. name) */
+	List	   *plinline;		/* optional inline function (qual. name) */
 	List	   *plvalidator;	/* optional validator function (qual. name) */
 	bool		pltrusted;		/* PL is trusted */
 } CreatePLangStmt;
@@ -1922,6 +1923,25 @@ typedef struct RemoveFuncStmt
 	bool		missing_ok;		/* skip error if missing? */
 } RemoveFuncStmt;
 
+/* ----------------------
+ *		DO Statement
+ *
+ * DoStmt is the raw parser output, InlineCodeBlock is the execution-time API
+ * ----------------------
+ */
+typedef struct DoStmt
+{
+	NodeTag		type;
+	List	   *args;			/* List of DefElem nodes */
+} DoStmt;
+
+typedef struct InlineCodeBlock
+{
+	NodeTag		type;
+	char	   *source_text;	/* source text of anonymous code block */
+	Oid			langOid;		/* OID of selected language */
+} InlineCodeBlock;
+
 /* ----------------------
  *		Drop Operator Class Statement
  * ----------------------