factor/extra/rosetta-code/inverted-index/inverted-index.factor

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Factor

! Copyright (c) 2012 Anonymous
! See http://factorcode.org/license.txt for BSD license.
USING: assocs fry io.encodings.utf8 io.files kernel sequences
sets splitting vectors ;
IN: rosetta-code.inverted-index
! http://rosettacode.org/wiki/Inverted_index
! An Inverted Index is a data structure used to create full text
! search.
! Given a set of text files, implement a program to create an
! inverted index. Also create a user interface to do a search
! using that inverted index which returns a list of files that
! contain the query term / terms. The search index can be in
! memory.
: file-words ( file -- assoc )
utf8 file-contents " ,;:!?.()[]{}\n\r" split harvest ;
: add-to-file-list ( files file -- files )
over [ swap [ adjoin ] keep ] [ nip 1vector ] if ;
: add-to-index ( words index file -- )
'[ _ [ _ add-to-file-list ] change-at ] each ;
: (index-files) ( files index -- )
[ [ [ file-words ] keep ] dip swap add-to-index ] curry each ;
: index-files ( files -- index )
H{ } clone [ (index-files) ] keep ;
: query ( terms index -- files )
[ at ] curry map [ ] [ intersect ] map-reduce ;