Change get_rule_expr so that when the input is a List, it displays the

list elements comma-separated instead of barfing.  This allows elimination
of half a dozen redundant copies of that behavior, and also makes the
world safe again for pg_get_expr() applied to pg_index.indexprs, per gripe
from Alexander Zhiltsov.

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 89a9e2451dd2756007c1a08dbbf9ffdd1c841004..a05bc8489ddfa123c2402e52e868d06d0568bf6a 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -3,7 +3,7 @@
  *                             back to source text
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.181 2004/09/13 20:07:13 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.182 2004/10/07 20:36:52 tgl Exp $
  *
  *       This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -2351,15 +2351,7 @@ get_insert_query_def(Query *query, deparse_context *context)
        {
                appendContextKeyword(context, "VALUES (",
                                                         -PRETTYINDENT_STD, PRETTYINDENT_STD, 2);
-               sep = "";
-               foreach(l, strippedexprs)
-               {
-                       Node       *expr = lfirst(l);
-
-                       appendStringInfo(buf, sep);
-                       sep = ", ";
-                       get_rule_expr(expr, context, false);
-               }
+               get_rule_expr((Node *) strippedexprs, context, false);
                appendStringInfoChar(buf, ')');
        }
        else
@@ -2938,7 +2930,9 @@ get_rule_expr(Node *node, deparse_context *context,
        /*
         * Each level of get_rule_expr must emit an indivisible term
         * (parenthesized if necessary) to ensure result is reparsed into the
-        * same expression tree.
+        * same expression tree.  The only exception is that when the input
+        * is a List, we emit the component items comma-separated with no
+        * surrounding decoration; this is convenient for most callers.
         *
         * There might be some work left here to support additional node types.
         */
@@ -3269,20 +3263,10 @@ get_rule_expr(Node *node, deparse_context *context,
                case T_ArrayExpr:
                        {
                                ArrayExpr  *arrayexpr = (ArrayExpr *) node;
-                               ListCell   *element;
-                               char       *sep;
 
                                appendStringInfo(buf, "ARRAY[");
-                               sep = "";
-                               foreach(element, arrayexpr->elements)
-                               {
-                                       Node       *e = (Node *) lfirst(element);
-
-                                       appendStringInfo(buf, sep);
-                                       get_rule_expr(e, context, true);
-                                       sep = ", ";
-                               }
-                               appendStringInfo(buf, "]");
+                               get_rule_expr((Node *) arrayexpr->elements, context, true);
+                               appendStringInfoChar(buf, ']');
                        }
                        break;
 
@@ -3348,40 +3332,20 @@ get_rule_expr(Node *node, deparse_context *context,
                case T_CoalesceExpr:
                        {
                                CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
-                               ListCell   *arg;
-                               char       *sep;
 
                                appendStringInfo(buf, "COALESCE(");
-                               sep = "";
-                               foreach(arg, coalesceexpr->args)
-                               {
-                                       Node       *e = (Node *) lfirst(arg);
-
-                                       appendStringInfo(buf, sep);
-                                       get_rule_expr(e, context, true);
-                                       sep = ", ";
-                               }
-                               appendStringInfo(buf, ")");
+                               get_rule_expr((Node *) coalesceexpr->args, context, true);
+                               appendStringInfoChar(buf, ')');
                        }
                        break;
 
                case T_NullIfExpr:
                        {
                                NullIfExpr *nullifexpr = (NullIfExpr *) node;
-                               ListCell   *arg;
-                               char       *sep;
 
                                appendStringInfo(buf, "NULLIF(");
-                               sep = "";
-                               foreach(arg, nullifexpr->args)
-                               {
-                                       Node       *e = (Node *) lfirst(arg);
-
-                                       appendStringInfo(buf, sep);
-                                       get_rule_expr(e, context, true);
-                                       sep = ", ";
-                               }
-                               appendStringInfo(buf, ")");
+                               get_rule_expr((Node *) nullifexpr->args, context, true);
+                               appendStringInfoChar(buf, ')');
                        }
                        break;
 
@@ -3478,6 +3442,21 @@ get_rule_expr(Node *node, deparse_context *context,
                        appendStringInfo(buf, "DEFAULT");
                        break;
 
+               case T_List:
+                       {
+                               char       *sep;
+                               ListCell   *l;
+
+                               sep = "";
+                               foreach(l, (List *) node)
+                               {
+                                       appendStringInfo(buf, sep);
+                                       get_rule_expr((Node *) lfirst(l), context, showimplicit);
+                                       sep = ", ";
+                               }
+                       }
+                       break;
+
                default:
                        elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
                        break;
@@ -3560,7 +3539,6 @@ get_func_expr(FuncExpr *expr, deparse_context *context,
        Oid                     argtypes[FUNC_MAX_ARGS];
        int                     nargs;
        ListCell   *l;
-       char       *sep;
 
        /*
         * If the function call came from an implicit coercion, then just show
@@ -3613,14 +3591,7 @@ get_func_expr(FuncExpr *expr, deparse_context *context,
 
        appendStringInfo(buf, "%s(",
                                         generate_function_name(funcoid, nargs, argtypes));
-
-       sep = "";
-       foreach(l, expr->args)
-       {
-               appendStringInfo(buf, sep);
-               sep = ", ";
-               get_rule_expr((Node *) lfirst(l), context, true);
-       }
+       get_rule_expr((Node *) expr->args, context, true);
        appendStringInfoChar(buf, ')');
 }
 
@@ -3787,8 +3758,6 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
 {
        StringInfo      buf = context->buf;
        Query      *query = (Query *) (sublink->subselect);
-       ListCell   *l;
-       char       *sep;
        bool            need_paren;
 
        if (sublink->subLinkType == ARRAY_SUBLINK)
@@ -3801,19 +3770,10 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
                need_paren = (list_length(sublink->lefthand) > 1);
                if (need_paren)
                        appendStringInfoChar(buf, '(');
-
-               sep = "";
-               foreach(l, sublink->lefthand)
-               {
-                       appendStringInfo(buf, sep);
-                       sep = ", ";
-                       get_rule_expr((Node *) lfirst(l), context, true);
-               }
-
+               get_rule_expr((Node *) sublink->lefthand, context, true);
                if (need_paren)
-                       appendStringInfo(buf, ") ");
-               else
-                       appendStringInfoChar(buf, ' ');
+                       appendStringInfoChar(buf, ')');
+               appendStringInfoChar(buf, ' ');
        }
 
        need_paren = true;