From 8830ce54d612411a99b7db8d6fc0c709d9071837 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 29 Nov 2001 22:57:37 +0000
Subject: [PATCH] Tweak plpgsql's expression reader to be smarter about
parentheses and to give more useful error messages. Stephen Szabo's example
of this morning ('loop' used as a variable name inside a subselect) works
correctly now, and a FOR that is misinterpreted as an integer FOR will draw
'missing .. at end of SQL expression', which is at least marginally helpful.
---
src/pl/plpgsql/src/gram.y | 148 ++++++++++++++++-------------------
src/pl/plpgsql/src/plpgsql.h | 4 +-
2 files changed, 68 insertions(+), 84 deletions(-)
diff --git a/src/pl/plpgsql/src/gram.y b/src/pl/plpgsql/src/gram.y
index abb2ac8e7f3..913d381144b 100644
--- a/src/pl/plpgsql/src/gram.y
+++ b/src/pl/plpgsql/src/gram.y
@@ -4,7 +4,7 @@
* procedural language
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v 1.28 2001/11/15 23:31:09 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v 1.29 2001/11/29 22:57:37 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@@ -39,7 +39,11 @@
#include "plpgsql.h"
-static PLpgSQL_expr *read_sqlstmt(int until, char *s, char *sqlstart);
+static PLpgSQL_expr *read_sql_construct(int until,
+ const char *expected,
+ bool isexpression,
+ const char *sqlstart);
+static PLpgSQL_expr *read_sql_stmt(const char *sqlstart);
static PLpgSQL_type *read_datatype(int tok);
static PLpgSQL_stmt *make_select_stmt(void);
static PLpgSQL_stmt *make_fetch_stmt(void);
@@ -407,7 +411,7 @@ decl_cursor_query :
PLpgSQL_expr *query;
plpgsql_ns_setlocal(false);
- query = plpgsql_read_expression(';', ";");
+ query = read_sql_stmt("SELECT ");
plpgsql_ns_setlocal(true);
$$ = query;
@@ -1002,74 +1006,20 @@ fori_varname : T_VARIABLE
fori_lower :
{
- int tok;
- int lno;
- PLpgSQL_dstring ds;
- int nparams = 0;
- int params[1024];
- char buf[32];
- PLpgSQL_expr *expr;
- int firsttok = 1;
-
- lno = yylineno;
- plpgsql_dstring_init(&ds);
- plpgsql_dstring_append(&ds, "SELECT ");
+ int tok;
- $$.reverse = 0;
- while((tok = yylex()) != K_DOTDOT)
+ tok = yylex();
+ if (tok == K_REVERSE)
{
- if (firsttok)
- {
- firsttok = 0;
- if (tok == K_REVERSE)
- {
- $$.reverse = 1;
- continue;
- }
- }
- if (tok == ';') break;
- if (plpgsql_SpaceScanned)
- plpgsql_dstring_append(&ds, " ");
- switch (tok)
- {
- case T_VARIABLE:
- params[nparams] = yylval.var->varno;
- sprintf(buf, " $%d ", ++nparams);
- plpgsql_dstring_append(&ds, buf);
- break;
-
- case T_RECFIELD:
- params[nparams] = yylval.recfield->rfno;
- sprintf(buf, " $%d ", ++nparams);
- plpgsql_dstring_append(&ds, buf);
- break;
-
- case T_TGARGV:
- params[nparams] = yylval.trigarg->dno;
- sprintf(buf, " $%d ", ++nparams);
- plpgsql_dstring_append(&ds, buf);
- break;
-
- default:
- if (tok == 0)
- {
- plpgsql_error_lineno = lno;
- elog(ERROR, "missing .. to terminate lower bound of for loop");
- }
- plpgsql_dstring_append(&ds, yytext);
- break;
- }
+ $$.reverse = 1;
+ }
+ else
+ {
+ $$.reverse = 0;
+ plpgsql_push_back_token(tok);
}
- expr = malloc(sizeof(PLpgSQL_expr) + sizeof(int) * nparams - sizeof(int));
- expr->dtype = PLPGSQL_DTYPE_EXPR;
- expr->query = strdup(plpgsql_dstring_get(&ds));
- expr->plan = NULL;
- expr->nparams = nparams;
- while(nparams-- > 0)
- expr->params[nparams] = params[nparams];
- plpgsql_dstring_free(&ds);
- $$.expr = expr;
+ $$.expr = plpgsql_read_expression(K_DOTDOT, "..");
}
stmt_fors : opt_label K_FOR lno fors_target K_IN K_SELECT expr_until_loop loop_body
@@ -1308,7 +1258,7 @@ stmt_execsql : execsql_start lno
new = malloc(sizeof(PLpgSQL_stmt_execsql));
new->cmd_type = PLPGSQL_STMT_EXECSQL;
new->lineno = $2;
- new->sqlstmt = read_sqlstmt(';', ";", $1);
+ new->sqlstmt = read_sql_stmt($1);
$$ = (PLpgSQL_stmt *)new;
}
@@ -1353,11 +1303,11 @@ stmt_open : K_OPEN lno cursor_varptr
switch (tok)
{
case K_SELECT:
- new->query = plpgsql_read_expression(';', ";");
+ new->query = read_sql_stmt("SELECT ");
break;
case K_EXECUTE:
- new->dynquery = plpgsql_read_expression(';', ";");
+ new->dynquery = read_sql_stmt("SELECT ");
break;
default:
@@ -1380,7 +1330,7 @@ stmt_open : K_OPEN lno cursor_varptr
elog(ERROR, "cursor %s has arguments", $3->refname);
}
- new->argquery = read_sqlstmt(';', ";", "SELECT ");
+ new->argquery = read_sql_stmt("SELECT ");
/* Remove the trailing right paren,
* because we want "select 1, 2", not
* "select (1, 2)".
@@ -1521,18 +1471,27 @@ lno :
PLpgSQL_expr *
-plpgsql_read_expression (int until, char *s)
+plpgsql_read_expression(int until, const char *expected)
{
- return read_sqlstmt(until, s, "SELECT ");
+ return read_sql_construct(until, expected, true, "SELECT ");
}
+static PLpgSQL_expr *
+read_sql_stmt(const char *sqlstart)
+{
+ return read_sql_construct(';', ";", false, sqlstart);
+}
static PLpgSQL_expr *
-read_sqlstmt (int until, char *s, char *sqlstart)
+read_sql_construct(int until,
+ const char *expected,
+ bool isexpression,
+ const char *sqlstart)
{
int tok;
int lno;
PLpgSQL_dstring ds;
+ int parenlevel = 0;
int nparams = 0;
int params[1024];
char buf[32];
@@ -1540,20 +1499,43 @@ read_sqlstmt (int until, char *s, char *sqlstart)
lno = yylineno;
plpgsql_dstring_init(&ds);
- plpgsql_dstring_append(&ds, sqlstart);
+ plpgsql_dstring_append(&ds, (char *) sqlstart);
- while((tok = yylex()) != until)
+ for (;;)
{
- if (tok == ';') break;
+ tok = yylex();
+ if (tok == '(')
+ parenlevel++;
+ else if (tok == ')')
+ {
+ parenlevel--;
+ if (parenlevel < 0)
+ elog(ERROR, "mismatched parentheses");
+ }
+ else if (parenlevel == 0 && tok == until)
+ break;
+ /*
+ * End of function definition is an error, and we don't expect to
+ * hit a semicolon either (unless it's the until symbol, in which
+ * case we should have fallen out above).
+ */
+ if (tok == 0 || tok == ';')
+ {
+ plpgsql_error_lineno = lno;
+ if (parenlevel != 0)
+ elog(ERROR, "mismatched parentheses");
+ if (isexpression)
+ elog(ERROR, "missing %s at end of SQL expression",
+ expected);
+ else
+ elog(ERROR, "missing %s at end of SQL statement",
+ expected);
+ break;
+ }
if (plpgsql_SpaceScanned)
plpgsql_dstring_append(&ds, " ");
switch (tok)
{
- case 0:
- plpgsql_error_lineno = lno;
- elog(ERROR, "missing %s at end of SQL statement", s);
- break;
-
case T_VARIABLE:
params[nparams] = yylval.var->varno;
sprintf(buf, " $%d ", ++nparams);
@@ -1618,6 +1600,8 @@ read_datatype(int tok)
if (tok == 0)
{
plpgsql_error_lineno = lno;
+ if (parenlevel != 0)
+ elog(ERROR, "mismatched parentheses");
elog(ERROR, "incomplete datatype declaration");
}
/* Possible followers for datatype in a declaration */
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index 7856a0dbb5f..041f2dd362a 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -3,7 +3,7 @@
* procedural language
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.23 2001/11/15 23:31:09 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.24 2001/11/29 22:57:37 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@@ -606,7 +606,7 @@ extern void plpgsql_dumptree(PLpgSQL_function * func);
* Externs in gram.y and scan.l
* ----------
*/
-extern PLpgSQL_expr *plpgsql_read_expression(int until, char *s);
+extern PLpgSQL_expr *plpgsql_read_expression(int until, const char *expected);
extern int plpgsql_yyparse(void);
extern int plpgsql_base_yylex(void);
extern int plpgsql_yylex(void);
--
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