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Special named constants

#!optional Constant
Special self-evaluating literal used in lambda parameter lists before optional parameters.

#!rest Constant
Special self-evaluating literal used in lambda parameter lists before the rest parameter.

#!key Constant
Special self-evaluating literal used in lambda parameter lists before keyword parameters.

#!eof Constant
The end-of-file object.

Note that if the Scheme reader sees this literal at top-level, it is returned literally. This is indistinguishable from coming to the end of the input file. If you do not want to end reading, but want the actual value of #!eof, you should quote it.

#!void Constant
The void value. Same as (values). If this is the value of an expression in a read-eval-print loop, nothing is printed.

#!null Constant
The Java null value. This is not really a Scheme value, but is useful when interfacing to low-level Java code.