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;