Customizing Read

Each input port has its own port read handler. This handler is invoked to read S-expressions from the port when the standard read procedure is applied to the port. A port read handler takes a single argument: the port being read. The return value is the value that was read from the port.

• (port-read-handler p) returns the current port read handler for the input port p.
• (port-read-handler p f) sets the handler for p to f.

The default port read handler reads standard Scheme expressions with MzScheme's built-in parser (see section 14.3).