<!--
-$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.85 2006/02/12 06:03:38 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.86 2006/02/12 06:37:05 tgl Exp $
-->
<chapter id="plpgsql">
</synopsis>
<para>
- This form of <literal>FOR</> creates a loop that iterates over a range of integer
- values. The variable
+ This form of <literal>FOR</> creates a loop that iterates over a range
+ of integer values. The variable
<replaceable>name</replaceable> is automatically defined as type
- <type>integer</> and exists only inside the loop. The two expressions giving
+ <type>integer</> and exists only inside the loop (any existing
+ definition of the variable name is ignored within the loop).
+ The two expressions giving
the lower and upper bound of the range are evaluated once when entering
the loop. The iteration step is normally 1, but is -1 when <literal>REVERSE</> is
specified.
<replaceable>statements</replaceable>
END LOOP <optional> <replaceable>label</replaceable> </optional>;
</synopsis>
- <replaceable>Target</replaceable> is a record variable, row variable,
- or a comma-separated list of simple variables and record/row fields
- which is successively assigned each row
+ The <replaceable>target</replaceable> is a record variable, row variable,
+ or comma-separated list of scalar variables.
+ The <replaceable>target</replaceable> is successively assigned each row
resulting from the <replaceable>query</replaceable> (which must be a
<command>SELECT</command> command) and the loop body is executed for each
row. Here is an example:
<literal>IN</> and <literal>LOOP</>. If <literal>..</> is not seen then
the loop is presumed to be a loop over rows. Mistyping the <literal>..</>
is thus likely to lead to a complaint along the lines of
- <quote>loop variable of loop over rows must be a record or row or scalar variable</>,
+ <quote>loop variable of loop over rows must be a record or row variable
+ or list of scalar variables</>,
rather than the simple syntax error one might expect to get.
</para>
</note>
* procedural language
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.84 2006/02/12 06:03:38 momjian Exp $
+ * $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.85 2006/02/12 06:37:05 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
static void check_assignable(PLpgSQL_datum *datum);
static PLpgSQL_row *read_into_scalar_list(const char *initial_name,
PLpgSQL_datum *initial_datum);
+static PLpgSQL_row *make_scalar_list1(const char *initial_name,
+ PLpgSQL_datum *initial_datum,
+ int lineno);
static void check_sql_expr(const char *stmt);
static void plpgsql_sql_error_callback(void *arg);
static void check_labels(const char *start_label,
const char *end_label);
-static PLpgSQL_row *make_scalar_list1(const char *name,
- PLpgSQL_datum *variable);
-
+
%}
%union {
{
char *name;
int lineno;
+ PLpgSQL_datum *scalar;
PLpgSQL_rec *rec;
PLpgSQL_row *row;
- PLpgSQL_datum *scalar;
} forvariable;
struct
{
}
else if ($2.scalar)
{
- new->row = make_scalar_list1($2.name, $2.scalar);
- check_assignable((PLpgSQL_datum *) new->row);
+ /* convert single scalar to list */
+ new->row = make_scalar_list1($2.name, $2.scalar, $2.lineno);
+ /* no need for check_assignable */
}
else
{
- plpgsql_error_lineno = $1;
- yyerror("loop variable of loop over rows must be a record, row, or scalar variable");
+ plpgsql_error_lineno = $2.lineno;
+ yyerror("loop variable of loop over rows must be a record or row variable or list of scalar variables");
}
new->query = expr;
PLpgSQL_expr *expr2;
PLpgSQL_var *fvar;
PLpgSQL_stmt_fori *new;
+ char *varname;
/* First expression is well-formed */
check_sql_expr(expr1->query);
expr2 = plpgsql_read_expression(K_LOOP, "LOOP");
- /* T_SCALAR identifier waits for converting */
- if ($2.scalar)
- {
- char *name;
- plpgsql_convert_ident($2.name, &name, 1);
- pfree($2.name);
- $2.name = name;
- }
+ /* should have had a single variable name */
+ plpgsql_error_lineno = $2.lineno;
+ if ($2.scalar && $2.row)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("integer FOR loop must have just one target variable")));
/* create loop's private variable */
+ plpgsql_convert_ident($2.name, &varname, 1);
fvar = (PLpgSQL_var *)
- plpgsql_build_variable($2.name,
+ plpgsql_build_variable(varname,
$2.lineno,
plpgsql_build_datatype(INT4OID,
-1),
}
else if ($2.scalar)
{
- new->row = make_scalar_list1($2.name, $2.scalar);
- check_assignable((PLpgSQL_datum *) new->row);
+ /* convert single scalar to list */
+ new->row = make_scalar_list1($2.name, $2.scalar, $2.lineno);
+ /* no need for check_assignable */
}
else
{
- plpgsql_error_lineno = $1;
- yyerror("loop variable of loop over rows must be record, row, or scalar variable");
+ plpgsql_error_lineno = $2.lineno;
+ yyerror("loop variable of loop over rows must be a record or row variable or list of scalar variables");
}
new->query = expr1;
* if any, because that's what we need for the loop-over-query case. Note
* that we must NOT apply check_assignable() or any other semantic check
* until we know what's what.
+ *
+ * However, if we see a comma-separated list of names, we know that it
+ * can't be an integer FOR loop and so it's OK to check the variables
+ * immediately. In particular, for T_WORD followed by comma, we should
+ * complain that the name is not known rather than say it's a syntax error.
+ * Note that the non-error result of this case sets *both* $$.scalar and
+ * $$.row; see the for_control production.
*/
for_variable : T_SCALAR
- {
- int tok;
- char *name;
-
- name = pstrdup(yytext);
- $$.scalar = yylval.scalar;
- $$.lineno = plpgsql_scanner_lineno();
+ {
+ int tok;
- if((tok = yylex()) == ',')
- {
- plpgsql_push_back_token(tok);
- $$.name = NULL;
- $$.row = read_into_scalar_list(name, $$.scalar);
- $$.rec = NULL;
- $$.scalar = NULL;
-
- pfree(name);
- }
- else
- {
- plpgsql_push_back_token(tok);
- $$.name = name;
- $$.row = NULL;
- $$.rec = NULL;
- }
+ $$.name = pstrdup(yytext);
+ $$.lineno = plpgsql_scanner_lineno();
+ $$.scalar = yylval.scalar;
+ $$.rec = NULL;
+ $$.row = NULL;
+ /* check for comma-separated list */
+ tok = yylex();
+ plpgsql_push_back_token(tok);
+ if (tok == ',')
+ $$.row = read_into_scalar_list($$.name, $$.scalar);
}
| T_WORD
{
- char *name;
+ int tok;
- plpgsql_convert_ident(yytext, &name, 1);
- $$.name = name;
+ $$.name = pstrdup(yytext);
$$.lineno = plpgsql_scanner_lineno();
+ $$.scalar = NULL;
$$.rec = NULL;
$$.row = NULL;
+ /* check for comma-separated list */
+ tok = yylex();
+ plpgsql_push_back_token(tok);
+ if (tok == ',')
+ {
+ plpgsql_error_lineno = $$.lineno;
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("\"%s\" is not a scalar variable",
+ $$.name)));
+ }
}
| T_RECORD
{
- $$.name = NULL;
+ $$.name = pstrdup(yytext);
$$.lineno = plpgsql_scanner_lineno();
+ $$.scalar = NULL;
$$.rec = yylval.rec;
$$.row = NULL;
}
| T_ROW
{
- $$.name = NULL;
+ $$.name = pstrdup(yytext);
$$.lineno = plpgsql_scanner_lineno();
+ $$.scalar = NULL;
$$.row = yylval.row;
$$.rec = NULL;
}
}
-static PLpgSQL_row *
-make_scalar_list1(const char *name,
- PLpgSQL_datum *variable)
-{
- PLpgSQL_row *row;
- check_assignable(variable);
-
- row = palloc(sizeof(PLpgSQL_row));
- row->dtype = PLPGSQL_DTYPE_ROW;
- row->refname = pstrdup("*internal*");
- row->lineno = plpgsql_scanner_lineno();
- row->rowtupdesc = NULL;
- row->nfields = 1;
- row->fieldnames = palloc(sizeof(char *) * 1);
- row->varnos = palloc(sizeof(int) * 1);
- row->fieldnames[0] = pstrdup(name);
- row->varnos[0] = variable->dno;
-
- plpgsql_adddatum((PLpgSQL_datum *)row);
-
- return row;
-}
-
-
static void
check_assignable(PLpgSQL_datum *datum)
{
}
/*
+ * Convert a single scalar into a "row" list. This is exactly
+ * like read_into_scalar_list except we never consume any input.
+ * In fact, since this can be invoked long after the source
+ * input was actually read, the lineno has to be passed in.
+ */
+static PLpgSQL_row *
+make_scalar_list1(const char *initial_name,
+ PLpgSQL_datum *initial_datum,
+ int lineno)
+{
+ PLpgSQL_row *row;
+
+ check_assignable(initial_datum);
+
+ row = palloc(sizeof(PLpgSQL_row));
+ row->dtype = PLPGSQL_DTYPE_ROW;
+ row->refname = pstrdup("*internal*");
+ row->lineno = lineno;
+ row->rowtupdesc = NULL;
+ row->nfields = 1;
+ row->fieldnames = palloc(sizeof(char *));
+ row->varnos = palloc(sizeof(int));
+ row->fieldnames[0] = pstrdup(initial_name);
+ row->varnos[0] = initial_datum->dno;
+
+ plpgsql_adddatum((PLpgSQL_datum *)row);
+
+ return row;
+}
+
+/*
* When the PL/PgSQL parser expects to see a SQL statement, it is very
* liberal in what it accepts; for example, we often assume an
* unrecognized keyword is the beginning of a SQL statement. This
ERROR: end label "outer_label" specified for unlabelled block
CONTEXT: compile of PL/pgSQL function "end_label4" near line 5
-- using list of scalars in fori and fore stmts
-create function for_vect() returns void as $$
+create function for_vect() returns void as $proc$
<<lbl>>declare a integer; b varchar; c varchar; r record;
begin
- -- old fori
- for i in 1 .. 10 loop
+ -- fori
+ for i in 1 .. 3 loop
raise notice '%', i;
end loop;
- for a in select 1 from generate_series(1,4) loop
+ -- fore with record var
+ for r in select gs as aa, 'BB' as bb, 'CC' as cc from generate_series(1,4) gs loop
+ raise notice '% % %', r.aa, r.bb, r.cc;
+ end loop;
+ -- fore with single scalar
+ for a in select gs from generate_series(1,4) gs loop
raise notice '%', a;
end loop;
- for a,b,c in select generate_series, 'BB','CC' from generate_series(1,4) loop
+ -- fore with multiple scalars
+ for a,b,c in select gs, 'BB','CC' from generate_series(1,4) gs loop
raise notice '% % %', a, b, c;
end loop;
-- using qualified names in fors, fore is enabled, disabled only for fori
- for lbl.a, lbl.b, lbl.c in execute E'select generate_series, \'bb\',\'cc\' from generate_series(1,4)' loop
+ for lbl.a, lbl.b, lbl.c in execute $$select gs, 'bb','cc' from generate_series(1,4) gs$$ loop
raise notice '% % %', a, b, c;
end loop;
end;
-$$ language plpgsql;
+$proc$ language plpgsql;
+select for_vect();
+NOTICE: 1
+NOTICE: 2
+NOTICE: 3
+NOTICE: 1 BB CC
+NOTICE: 2 BB CC
+NOTICE: 3 BB CC
+NOTICE: 4 BB CC
+NOTICE: 1
+NOTICE: 2
+NOTICE: 3
+NOTICE: 4
+NOTICE: 1 BB CC
+NOTICE: 2 BB CC
+NOTICE: 3 BB CC
+NOTICE: 4 BB CC
+NOTICE: 1 bb cc
+NOTICE: 2 bb cc
+NOTICE: 3 bb cc
+NOTICE: 4 bb cc
+ for_vect
+----------
+
+(1 row)
+
end;
$$ language plpgsql;
-
-- using list of scalars in fori and fore stmts
-create function for_vect() returns void as $$
+create function for_vect() returns void as $proc$
<<lbl>>declare a integer; b varchar; c varchar; r record;
begin
- -- old fori
- for i in 1 .. 10 loop
+ -- fori
+ for i in 1 .. 3 loop
raise notice '%', i;
end loop;
- for a in select 1 from generate_series(1,4) loop
+ -- fore with record var
+ for r in select gs as aa, 'BB' as bb, 'CC' as cc from generate_series(1,4) gs loop
+ raise notice '% % %', r.aa, r.bb, r.cc;
+ end loop;
+ -- fore with single scalar
+ for a in select gs from generate_series(1,4) gs loop
raise notice '%', a;
end loop;
- for a,b,c in select generate_series, 'BB','CC' from generate_series(1,4) loop
+ -- fore with multiple scalars
+ for a,b,c in select gs, 'BB','CC' from generate_series(1,4) gs loop
raise notice '% % %', a, b, c;
end loop;
-- using qualified names in fors, fore is enabled, disabled only for fori
- for lbl.a, lbl.b, lbl.c in execute E'select generate_series, \'bb\',\'cc\' from generate_series(1,4)' loop
+ for lbl.a, lbl.b, lbl.c in execute $$select gs, 'bb','cc' from generate_series(1,4) gs$$ loop
raise notice '% % %', a, b, c;
end loop;
end;
-$$ language plpgsql;
+$proc$ language plpgsql;
+
+select for_vect();
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