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annotate src/option_key_fn.sml @ 2244:e4a7e3cd6f11

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Use uniform representation of comparisons for better simplification.
author Ziv Scully <ziv@mit.edu>
date Mon, 20 Jul 2015 23:25:44 -0700
parents 88cc0f44c940
children
rev   line source
ziv@2244 1 functor OptionKeyFn(K : ORD_KEY)
ziv@2244 2 : ORD_KEY where type ord_key = K.ord_key option = struct
ziv@2240 3
ziv@2240 4 type ord_key = K.ord_key option
ziv@2240 5
ziv@2240 6 val compare =
ziv@2240 7 fn (NONE, NONE) => EQUAL
ziv@2240 8 | (NONE, _) => LESS
ziv@2240 9 | (_, NONE) => GREATER
ziv@2240 10 | (SOME x, SOME y) => K.compare (x, y)
ziv@2240 11
ziv@2240 12 end