Reimplement parsing and storage of default expressions and constraint

expressions in CREATE TABLE.  There is no longer an emasculated expression
syntax for these things; it's full a_expr for constraints, and b_expr
for defaults (unfortunately the fact that NOT NULL is a part of the
column constraint syntax causes a shift/reduce conflict if you try a_expr.
Oh well --- at least parenthesized boolean expressions work now).  Also,
stored expression for a column default is not pre-coerced to the column
type; we rely on transformInsertStatement to do that when the default is
actually used.  This means "f1 datetime default 'now'" behaves the way
people usually expect it to.
BTW, all the support code is now there to implement ALTER TABLE ADD
CONSTRAINT and ALTER TABLE ADD COLUMN with a default value.  I didn't
actually teach ALTER TABLE to call it, but it wouldn't be much work.

1 files changed, 81 insertions, 76 deletions

diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 276d28b3aa1..4bcf79a7277 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -5,7 +5,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- *	$Id: analyze.c,v 1.119 1999/09/18 19:07:12 tgl Exp $
+ *	$Id: analyze.c,v 1.120 1999/10/03 23:55:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -396,7 +396,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 				if (namestrcmp(&(thisatt->attname), resnode->resname) == 0)
 					break;
 			}
-			if (tl != NIL)		/* something given for this attr */
+			if (tl != NIL)		/* found TLE for this attr */
 				continue;
 			/*
 			 * No user-supplied value, so add a targetentry with DEFAULT expr
@@ -573,7 +573,6 @@ transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
 	q = makeNode(Query);
 	q->commandType = CMD_UTILITY;
 
-	elements = stmt->tableElts;
 	constraints = stmt->constraints;
 	columns = NIL;
 	dlist = NIL;
@@ -581,7 +580,7 @@ transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
 	/*
 	 * Run through each primary element in the table creation clause
 	 */
-	while (elements != NIL)
+	foreach(elements, stmt->tableElts)
 	{
 		element = lfirst(elements);
 		switch (nodeTag(element))
@@ -594,19 +593,31 @@ transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
 				if (column->is_sequence)
 				{
 					char	   *sname;
-					char	   *cstring;
+					char	   *qstring;
+					A_Const	   *snamenode;
+					FuncCall   *funccallnode;
 					CreateSeqStmt *sequence;
 
 					sname = makeObjectName(stmt->relname, column->colname,
 										   "seq");
+					/*
+					 * Create an expression tree representing the function
+					 * call  nextval('"sequencename"')
+					 */
+					qstring = palloc(strlen(sname) + 2 + 1);
+					sprintf(qstring, "\"%s\"", sname);
+					snamenode = makeNode(A_Const);
+					snamenode->val.type = T_String;
+					snamenode->val.val.str = qstring;
+					funccallnode = makeNode(FuncCall);
+					funccallnode->funcname = "nextval";
+					funccallnode->args = lcons(snamenode, NIL);
+
 					constraint = makeNode(Constraint);
 					constraint->contype = CONSTR_DEFAULT;
 					constraint->name = sname;
-					cstring = palloc(10 + strlen(constraint->name) + 3 + 1);
-					strcpy(cstring, "nextval('\"");
-					strcat(cstring, constraint->name);
-					strcat(cstring, "\"')");
-					constraint->def = cstring;
+					constraint->raw_expr = (Node *) funccallnode;
+					constraint->cooked_expr = NULL;
 					constraint->keys = NULL;
 
 					column->constraints = lappend(column->constraints, constraint);
@@ -628,69 +639,65 @@ transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
 					blist = lcons(sequence, NIL);
 				}
 
-				/* Check for column constraints, if any... */
-				if (column->constraints != NIL)
+				/* Process column constraints, if any... */
+				foreach(clist, column->constraints)
 				{
-					clist = column->constraints;
-					while (clist != NIL)
+					constraint = lfirst(clist);
+					switch (constraint->contype)
 					{
-						constraint = lfirst(clist);
-						switch (constraint->contype)
-						{
-							case CONSTR_NULL:
-
-								/*
-								 * We should mark this explicitly, so we
-								 * can tell if NULL and NOT NULL are both
-								 * specified
-								 */
-								if (column->is_not_null)
-									elog(ERROR, "CREATE TABLE/(NOT) NULL conflicting declaration"
-										 " for '%s.%s'", stmt->relname, column->colname);
-								column->is_not_null = FALSE;
-								break;
-
-							case CONSTR_NOTNULL:
-								if (column->is_not_null)
-									elog(ERROR, "CREATE TABLE/NOT NULL already specified"
-										 " for '%s.%s'", stmt->relname, column->colname);
-								column->is_not_null = TRUE;
-								break;
-
-							case CONSTR_DEFAULT:
-								if (column->defval != NULL)
-									elog(ERROR, "CREATE TABLE/DEFAULT multiple values specified"
-										 " for '%s.%s'", stmt->relname, column->colname);
-								column->defval = constraint->def;
-								break;
-
-							case CONSTR_PRIMARY:
-								if (constraint->name == NULL)
-									constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
-								if (constraint->keys == NIL)
-									constraint->keys = lappend(constraint->keys, column);
-								dlist = lappend(dlist, constraint);
-								break;
-
-							case CONSTR_UNIQUE:
-								if (constraint->name == NULL)
-									constraint->name = makeObjectName(stmt->relname, column->colname, "key");
-								if (constraint->keys == NIL)
-									constraint->keys = lappend(constraint->keys, column);
-								dlist = lappend(dlist, constraint);
-								break;
-
-							case CONSTR_CHECK:
-								constraints = lappend(constraints, constraint);
-								if (constraint->name == NULL)
-									constraint->name = makeObjectName(stmt->relname, column->colname, NULL);
-								break;
-
-							default:
-								elog(ERROR, "parser: unrecognized constraint (internal error)", NULL);
-								break;
-						}
-						clist = lnext(clist);
+						case CONSTR_NULL:
+
+							/*
+							 * We should mark this explicitly, so we
+							 * can tell if NULL and NOT NULL are both
+							 * specified
+							 */
+							if (column->is_not_null)
+								elog(ERROR, "CREATE TABLE/(NOT) NULL conflicting declaration"
+									 " for '%s.%s'", stmt->relname, column->colname);
+							column->is_not_null = FALSE;
+							break;
+
+						case CONSTR_NOTNULL:
+							if (column->is_not_null)
+								elog(ERROR, "CREATE TABLE/NOT NULL already specified"
+									 " for '%s.%s'", stmt->relname, column->colname);
+							column->is_not_null = TRUE;
+							break;
+
+						case CONSTR_DEFAULT:
+							if (column->raw_default != NULL)
+								elog(ERROR, "CREATE TABLE/DEFAULT multiple values specified"
+									 " for '%s.%s'", stmt->relname, column->colname);
+							column->raw_default = constraint->raw_expr;
+							Assert(constraint->cooked_expr == NULL);
+							break;
+
+						case CONSTR_PRIMARY:
+							if (constraint->name == NULL)
+								constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
+							if (constraint->keys == NIL)
+								constraint->keys = lappend(constraint->keys, column);
+							dlist = lappend(dlist, constraint);
+							break;
+
+						case CONSTR_UNIQUE:
+							if (constraint->name == NULL)
+								constraint->name = makeObjectName(stmt->relname, column->colname, "key");
+							if (constraint->keys == NIL)
+								constraint->keys = lappend(constraint->keys, column);
+							dlist = lappend(dlist, constraint);
+							break;
+
+						case CONSTR_CHECK:
+							if (constraint->name == NULL)
+								constraint->name = makeObjectName(stmt->relname, column->colname, NULL);
+							constraints = lappend(constraints, constraint);
+							break;
+
+						default:
+							elog(ERROR, "parser: unrecognized constraint (internal error)", NULL);
+							break;
 					}
 				}
 				break;
@@ -715,19 +722,17 @@ transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
 
 					case CONSTR_NOTNULL:
 					case CONSTR_DEFAULT:
-						elog(ERROR, "parser: illegal context for constraint (internal error)", NULL);
+						elog(ERROR, "parser: illegal context for constraint (internal error)");
 						break;
 					default:
-						elog(ERROR, "parser: unrecognized constraint (internal error)", NULL);
+						elog(ERROR, "parser: unrecognized constraint (internal error)");
 						break;
 				}
 				break;
 
 			default:
-				elog(ERROR, "parser: unrecognized node (internal error)", NULL);
+				elog(ERROR, "parser: unrecognized node (internal error)");
 		}
-
-		elements = lnext(elements);
 	}
 
 	stmt->tableElts = columns;