compare-with-spec ( obj1 obj2 sort-spec -- <=> )
Sorting by multiple keys

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sort-with-spec ( seq sort-spec -- seq' )

Vocabulary
sorting.specification

Inputs

obj1	an object
obj2	an object
sort-spec	a sequence of sequences of accessors/quotations and a comparator

Outputs

<=>	+lt+, +eq+ or +gt+

Word description
Compares two objects using a chain of intrinsic linear orders such that if two objects are +eq+, then the next ordering is tried.

Definition

USING: arrays kernel math.order quotations sequences ;

IN: sorting.specification

: compare-with-spec ( obj1 obj2 sort-spec -- <=> )
    [
        dup array? [
            unclip-last-slice [
                [
                    dup quotation?
                    [ call-accessor ] [ execute-accessor ] if
                ] each
            ] dip
        ] when execute-comparator
    ] 2with map-find drop +eq+ or ;