5.10 Object Printing

To customize the way that a class instance is printed by write or display, implement the printable<%> interface.

printable<%> : interface?

The printable<%> interface includes only the custom-write and custom-print methods. Each accepts a single argument, which is the destination port to write or display the object.

Calls to the custom-write or custom-display are like calls to a procedure attached to a structure type through the prop:custom-write property. In particular, recursive printing can trigger an escape from the call.

See prop:custom-write for more information. The printable<%> interface is implemented with interface* and prop:custom-write.