/*
* Parse a function call
*
* For historical reasons, Postgres tries to treat the notations tab.col
* and col(tab) as equivalent: if a single-argument function call has an
* argument of complex type and the (unqualified) function name matches
* any attribute of the type, we take it as a column projection. Conversely
* a function of a single complex-type argument can be written like a
* column reference, allowing functions to act like computed columns.
*
* Hence, both cases come through here. The is_column parameter tells us
* which syntactic construct is actually being dealt with, but this is
* intended to be used only to deliver an appropriate error message,
* not to affect the semantics. When is_column is true, we should have
* a single argument (the putative table), unqualified function name
* equal to the column name, and no aggregate or variadic decoration.
*
* The argument expressions (in fargs) must have been transformed already.
*/
Node *
ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
bool agg_star, bool agg_distinct, bool func_variadic,
WindowDef *over, bool is_column, int location)
{
Oid rettype;
Oid funcid;
ListCell *l;
ListCell *nextl;
Node *first_arg = NULL;
int nargs;
int nargsplusdefs;
Oid actual_arg_types[FUNC_MAX_ARGS];
Oid *declared_arg_types;
List *argdefaults;
Node *retval;
bool retset;
int nvargs;
FuncDetailCode fdresult;
/*
* Most of the rest of the parser just assumes that functions do not have
* more than FUNC_MAX_ARGS parameters. We have to test here to protect
* against array overruns, etc. Of course, this may not be a function,
* but the test doesn't hurt.
*/
if (list_length(fargs) > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg_plural("cannot pass more than %d argument to a function",
"cannot pass more than %d arguments to a function",
FUNC_MAX_ARGS,
FUNC_MAX_ARGS),
parser_errposition(pstate, location)));
/*
* Extract arg type info in preparation for function lookup.
*
* If any arguments are Param markers of type VOID, we discard them from
* the parameter list. This is a hack to allow the JDBC driver to not
* have to distinguish "input" and "output" parameter symbols while
* parsing function-call constructs. We can't use foreach() because we
* may modify the list ...
*/
nargs = 0;
for (l = list_head(fargs); l != NULL; l = nextl)
{
Node *arg = lfirst(l);
Oid argtype = exprType(arg);
nextl = lnext(l);
if (argtype == VOIDOID && IsA(arg, Param) &&!is_column)
{
fargs = list_delete_ptr(fargs, arg);
continue;
}
actual_arg_types[nargs++] = argtype;
}
if (fargs)
{
first_arg = linitial(fargs);
Assert(first_arg != NULL);
}
/*
* Check for column projection: if function has one argument, and that
* argument is of complex type, and function name is not qualified, then
* the "function call" could be a projection. We also check that there
* wasn't any aggregate or variadic decoration.
*/
if (nargs == 1 && !agg_star && !agg_distinct && over == NULL &&
!func_variadic && list_length(funcname) == 1)
{
Oid argtype = actual_arg_types[0];
if (argtype == RECORDOID || ISCOMPLEX(argtype))
{
retval = ParseComplexProjection(pstate,
strVal(linitial(funcname)),
first_arg,
location);
if (retval)
return retval;
/*
* If ParseComplexProjection doesn't recognize it as a projection,
* just press on.
*/
}
}
/*
* Okay, it's not a column projection, so it must really be a function.
* func_get_detail looks up the function in the catalogs, does
* disambiguation for polymorphic functions, handles inheritance, and
* returns the funcid and type and set or singleton status of the
* function's return value. It also returns the true argument types to
* the function. In the case of a variadic function call, the reported
* "true" types aren't really what is in pg_proc: the variadic argument is
* replaced by a suitable number of copies of its element type. We'll fix
* it up below. We may also have to deal with default arguments.
*/
fdresult = func_get_detail(funcname, fargs, nargs, actual_arg_types,
!func_variadic, true,
&funcid, &rettype, &retset, &nvargs,
&declared_arg_types, &argdefaults);
if (fdresult == FUNCDETAIL_COERCION)
{
/*
* We interpreted it as a type coercion. coerce_type can handle these
* cases, so why duplicate code...
*/
return coerce_type(pstate, linitial(fargs),
actual_arg_types[0], rettype, -1,
COERCION_EXPLICIT, COERCE_EXPLICIT_CALL, location);
}
else if (fdresult == FUNCDETAIL_NORMAL)
{
/*
* Normal function found; was there anything indicating it must be an
* aggregate?
*/
if (agg_star)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("%s(*) specified, but %s is not an aggregate function",
NameListToString(funcname),
NameListToString(funcname)),
parser_errposition(pstate, location)));
if (agg_distinct)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("DISTINCT specified, but %s is not an aggregate function",
NameListToString(funcname)),
parser_errposition(pstate, location)));
if (over)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("OVER specified, but %s is not a window function nor an aggregate function",
NameListToString(funcname)),
parser_errposition(pstate, location)));
}
else if (!(fdresult == FUNCDETAIL_AGGREGATE ||
fdresult == FUNCDETAIL_WINDOWFUNC))
{
/*
* Oops. Time to die.
*
* If we are dealing with the attribute notation rel.function, give an
* error message that is appropriate for that case.
*/
if (is_column)
{
Assert(nargs == 1);
Assert(list_length(funcname) == 1);
unknown_attribute(pstate, first_arg, strVal(linitial(funcname)),
location);
}
/*
* Else generate a detailed complaint for a function
*/
if (fdresult == FUNCDETAIL_MULTIPLE)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
errmsg("function %s is not unique",
func_signature_string(funcname, nargs,
actual_arg_types)),
errhint("Could not choose a best candidate function. "
"You might need to add explicit type casts."),
parser_errposition(pstate, location)));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("function %s does not exist",
func_signature_string(funcname, nargs,
actual_arg_types)),
errhint("No function matches the given name and argument types. "
"You might need to add explicit type casts."),
parser_errposition(pstate, location)));
}
/*
* If there are default arguments, we have to include their types in
* actual_arg_types for the purpose of checking generic type consistency.
* However, we do NOT put them into the generated parse node, because
* their actual values might change before the query gets run. The
* planner has to insert the up-to-date values at plan time.
*/
nargsplusdefs = nargs;
foreach(l, argdefaults)
{
Node *expr = (Node *) lfirst(l);
/* probably shouldn't happen ... */
if (nargsplusdefs >= FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg_plural("cannot pass more than %d argument to a function",
"cannot pass more than %d arguments to a function",
FUNC_MAX_ARGS,
FUNC_MAX_ARGS),
parser_errposition(pstate, location)));
actual_arg_types[nargsplusdefs++] = exprType(expr);
}
/*
* Parse a function call
*
* For historical reasons, Postgres tries to treat the notations tab.col
* and col(tab) as equivalent: if a single-argument function call has an
* argument of complex type and the (unqualified) function name matches
* any attribute of the type, we take it as a column projection. Conversely
* a function of a single complex-type argument can be written like a
* column reference, allowing functions to act like computed columns.
*
* Hence, both cases come through here. The is_column parameter tells us
* which syntactic construct is actually being dealt with, but this is
* intended to be used only to deliver an appropriate error message,
* not to affect the semantics. When is_column is true, we should have
* a single argument (the putative table), unqualified function name
* equal to the column name, and no aggregate decoration.
*
* The argument expressions (in fargs) must have been transformed already.
*/
Node *
ParseFuncOrColumn(ParseState *pstate, List *funcname, List *fargs,
bool agg_star, bool agg_distinct, bool is_column)
{
Oid rettype;
Oid funcid;
ListCell *l;
Node *first_arg = NULL;
int nargs = list_length(fargs);
int argn;
Oid actual_arg_types[FUNC_MAX_ARGS];
Oid *declared_arg_types;
Node *retval;
bool retset;
FuncDetailCode fdresult;
/*
* Most of the rest of the parser just assumes that functions do not
* have more than FUNC_MAX_ARGS parameters. We have to test here to
* protect against array overruns, etc. Of course, this may not be a
* function, but the test doesn't hurt.
*/
if (nargs > FUNC_MAX_ARGS)
ereport(ERROR,
(errcode(ERRCODE_TOO_MANY_ARGUMENTS),
errmsg("cannot pass more than %d arguments to a function",
FUNC_MAX_ARGS)));
if (fargs)
{
first_arg = linitial(fargs);
Assert(first_arg != NULL);
}
/*
* Check for column projection: if function has one argument, and that
* argument is of complex type, and function name is not qualified,
* then the "function call" could be a projection. We also check that
* there wasn't any aggregate decoration.
*/
if (nargs == 1 && !agg_star && !agg_distinct && list_length(funcname) == 1)
{
Oid argtype = exprType(first_arg);
if (argtype == RECORDOID || ISCOMPLEX(argtype))
{
retval = ParseComplexProjection(pstate,
strVal(linitial(funcname)),
first_arg);
if (retval)
return retval;
/*
* If ParseComplexProjection doesn't recognize it as a
* projection, just press on.
*/
}
}
/*
* Okay, it's not a column projection, so it must really be a
* function. Extract arg type info in preparation for function lookup.
*/
MemSet(actual_arg_types, 0, FUNC_MAX_ARGS * sizeof(Oid));
argn = 0;
foreach(l, fargs)
{
Node *arg = lfirst(l);
actual_arg_types[argn++] = exprType(arg);
}