| obj | any object |
| z | complex number object |
| x | real number object |
| y | real number object |
| q | rational number object |
| n | integer object |
| k | exact non-negative integer object |
| bool | boolean (#f or #t) |
| octet | exact integer object in {0, ..., 255} |
| byte | exact integer object in { - 128, ..., 127} |
| char | character |
| pair | pair |
| vector | vector |
| string | string |
| condition | condition |
| bytevector | bytevector |
| proc | procedure |