removed arrayaccess, added __invoke as a shortcut for Stream::item( )

stream.php

@@ -1,5 +1,5 @@
 <?php
-class Stream implements Iterator, ArrayAccess {
+class Stream implements Iterator {
 	private $tailPromise;
 	private $headValue;
 	private $pointer;
@@ -39,29 +39,10 @@ public function valid() {
 	}
 	/* end of iterator methods */
 
-	/* arrayaccess methods */
-	public function offsetGet( $n ) {
+	public function __invoke( $n ) {
 		return $this->item( $n );
 	}
 
-	public function offsetExists( $n ) {
-		try {
-			$this->item( $n );
-		} catch( Exception $e ) {
-			return false;
-		}
-		return true;
-	}
-
-	public function offsetSet( $n, $v ) {
-		// how to reconcile with a tailpromise?
-	}
-
-	public function offsetUnset( $n ) {
-		// do some cleverness with Stream->drop( $n )?
-	}
-	/* end of arrayaccess methods */
-
 	public function blank() {
 		return ( $this->headValue === null );
 	}

test/finite_stream.php

@@ -29,9 +29,9 @@ public function test_has_correct_values() {
 
 	public function test_array_access_gives_correct_values() {
 		$s = $this->make_static_stream();
-		$this->assertEquals( 10, $s[0] );
-		$this->assertEquals( 20, $s[1] );
-		$this->assertEquals( 30, $s[2] );		
+		$this->assertEquals( 10, $s(0) );
+		$this->assertEquals( 20, $s(1) );
+		$this->assertEquals( 30, $s(2) );		
 	}
 
 	public function test_car_cdr_behavior() {