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refactor a bit, document sort-by

db4
Doug Coleman 2009-04-03 19:49:49 -05:00
parent 8fdb3bb27a
commit c97ca399d8
2 changed files with 15 additions and 7 deletions
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15
basis/sorting/slots/slots-docs.factor
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@ -14,7 +14,7 @@ HELP: compare-slots
HELP: sort-by-slots
{ $values
{ "seq" sequence } { "sort-specs" "a sequence of accessors ending with a comparator" }
{ "seq'" sequence }
{ "sortedseq" sequence }
}
{ $description "Sorts a sequence of tuples by the sort-specs in " { $snippet "sort-spec" } ". A sort-spec is a sequence of slot accessors ending in a comparator." }
{ $examples
@ -39,11 +39,20 @@ HELP: split-by-slots
}
{ $description "Splits a sequence of tuples into a sequence of slices of tuples that have the same values in all slots in the accessor sequence. This word is only useful for splitting a sorted sequence, but is more efficient than partitioning in such a case." } ;
HELP: sort-by
{ $values
{ "seq" sequence } { "sort-seq" "a sequence of comparators" }
{ "sortedseq" sequence }
}
{ $description "Sorts a sequence by comparing elements by comparators, using subsequent comparators when there is a tie." } ;
ARTICLE: "sorting.slots" "Sorting by slots"
"The " { $vocab-link "sorting.slots" } " vocabulary can sort tuples by slot in ascending or descending order, using subsequent slots as tie-breakers." $nl
"Comparing two objects by a sequence of slots:"
{ $subsection compare-slots }
"Sorting a sequence by a sequence of slots:"
{ $subsection sort-by-slots } ;
"Sorting a sequence of tuples by a slot/comparator pairs:"
{ $subsection sort-by-slots }
"Sorting a sequence by a sequence of comparators:"
{ $subsection sort-by } ;
ABOUT: "sorting.slots"

7
basis/sorting/slots/slots.factor
View File

@ -8,7 +8,7 @@ IN: sorting.slots
<PRIVATE
: short-circuit-comparator ( word -- quot )
'[ _ execute dup +eq+ eq? [ drop f ] when ] ; inline
execute dup +eq+ eq? [ drop f ] when ; inline
: slot-comparator ( seq -- quot )
[
@ -16,7 +16,7 @@ IN: sorting.slots
[ '[ [ _ execute ] bi@ ] ] map concat
] [
peek
'[ @ _ execute dup +eq+ eq? [ drop f ] when ]
'[ @ _ short-circuit-comparator ]
] bi ;
PRIVATE>
@ -29,12 +29,11 @@ MACRO: compare-slots ( sort-specs -- <=> )
'[ _ compare-slots ] sort ;
MACRO: compare-seq ( seq -- quot )
[ short-circuit-comparator ] map '[ _ 2|| +eq+ or ] ;
[ '[ _ short-circuit-comparator ] ] map '[ _ 2|| +eq+ or ] ;
: sort-by ( seq sort-seq -- sortedseq )
'[ _ compare-seq ] sort ;
MACRO: split-by-slots ( accessor-seqs -- quot )
[ [ '[ [ _ execute ] bi@ ] ] map concat [ = ] compose ] map
'[ [ _ 2&& ] slice monotonic-slice ] ;