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In article <24169@shemp.CS.UCLA.EDU> firstname.lastname@example.org writes:
] I think that the specification of Scheme, as well as many Scheme programs,
] would be made more elegant if an "unspecified-object" analogous to NaN in
] the IEEE numeric standard were introduced. Functions which return
] unspecified values now would be required to return an "unspecified-object"
] -- Brad
I agree quite strongly with this. The scheme that I've been hacking at
lately is Ed Puckett's AmiScheme for the Amiga. In Amischeme, there is
an object called #u, the sole member of the "unit" domain. Any
internal function that the standard says returns an "unspecified"
result returns #u. In my functions, I try to do this also - any
function that exists for its side-effects returns #u. In addition to
adding clarity, it has proven quite useful for debugging.
=| Mark Craig Carroll: <MC> |=
=| email@example.com,...!rutgers!topaz!mccarrol |=
=| "Your only obligation in any lifetime is to be true to yourself" |=
=| -Richard Bach,_Illusions_ |=