<=> ( obj1 obj2 -- <=> )
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>=< ( obj1 obj2 -- >=< )

Vocabulary
math.order

Inputs

obj1	an object
obj2	an object

Outputs

<=>	an ordering specifier

Generic word contract
Compares two objects using an intrinsic linear order, for example, the natural order for real numbers and lexicographic order for strings.

The output value is one of the following:

•	+lt+ - indicating that obj1 precedes obj2
•	+eq+ - indicating that obj1 is equal to obj2
•	+gt+ - indicating that obj1 follows obj2

See also
>=<

Definition

IN: math.order

GENERIC: <=> ( obj1 obj2 -- <=> )

Methods

USING: accessors kernel math math.order sorting.human ;

M: alphanum <=>
    [ obj>> ] bi@ 2dup [ integer? ] bi@ xor
    [ drop integer? +lt+ +gt+ ? ] [ <=> ] if ;


USING: accessors kernel math.order
rosetta-code.knapsack-unbounded ;

M:: bounty <=> ( a b -- <=> )
    a valid-bounty?
    [ b valid-bounty? [ a b [ value>> ] compare ] [ +gt+ ] if ]
    [ b valid-bounty? +lt+ +eq+ ? ] if ;


USING: decimals kernel math.order ;

M: decimal <=>
    2dup before? [ 2drop +lt+ ] [ equal? +eq+ +gt+ ? ] if ;
    inline


USING: calendar math.order ;

M: duration <=> [ duration>years ] compare ;


USING: accessors io.pathnames math.order ;

M: pathname <=> [ string>> ] compare ;


USING: math math.order math.order.private ;

M: real <=> real<=> ; inline


USING: kernel math.order semver semver.private ;

M: semver <=>
    2dup major<=> dup +eq+ eq? [
        drop 2dup minor<=> dup +eq+ eq? [
            drop 2dup patch<=> dup +eq+ eq?
            [ drop prerelease<=> ] [ 2nip ] if
        ] [ 2nip ] if
    ] [ 2nip ] if ;


USING: kernel math.order sequences sequences.private ;

M: sequence <=>
    [ mismatch ] 2keep pick
    [ 2nth-unsafe <=> ] [ [ length ] compare nip ] if ;


USING: calendar classes.tuple math.order ;

M: timestamp <=> [ >gmt tuple-slots ] compare ;


USING: accessors compiler.cfg.ssa.interference math.order
sorting.specification ;

M: vreg-info <=>
    { { pre-of>> <=> } { def-index>> <=> } } compare-with-spec ;


USING: accessors arrays kernel math.order words ;

M: word <=> [ [ name>> ] [ vocabulary>> ] bi 2array ] compare ;