proposal: searching in array function - array_position

Hi

I am proposing a simple function, that returns a position of element in
array.

FUNCTION array_position(anyarray, anyelement) RETURNS int

Implementation is simple (plpgsql code)

CREATE OR REPLACE FUNCTION array_position(anyarray, anyelement)
RETURNS int AS $$
DECLARE i int := 0;
BEGIN
FOREACH a IN ARRAY $1
LOOP
IF a = $1 THEN
RETURN i;
END IF;
i := i + 1;
END LOOP;
RETURN NULL;
END;
$$ LANGUAGE plpgsql IMMUTABLE STRICT;

A possible benefits:

1. speed in plpgsql applications
2. reduced length of SQL functions

Ideas, comments, notices?

Regards

Pavel