go-query simple []int32 query library 
Blazingly fast query engine
Used to build and execute queries such as:
n := 10 // total docs in index
And(
Term(n, "name:hello", []int32{4, 5}),
Term(n, "name:world", []int32{4, 100}),
Or(
Term(n, "country:nl", []int32{20,30}),
Term(n, "country:uk", []int32{4,30}),
)
)- scoring: only
idfscore (for now) - supported queries:
or,and,and_not,dis_max,constant,term normalizers: space_between_digits, lowercase, trim, cleanup, etctokenizers: left edge, custom, charngram, unique, soundex etcgo-query-index: useful example of how to build more complex search engine with the library
query
Usually when you have inverted index you endup having something like:
data := []*Document{}
index := map[string][]int32{}
for docId, d := range document {
for _, token := range tokenize(normalize(d.Name)) {
index[token] = append(index[token],docId)
}
}then from documents like {hello world}, {hello}, {new york}, {new world} you get inverted index in the form of:
{
"hello": [0,1],
"world": [0,3],
"new": [2,3],
"york": [2]
}anyway, if you want to read more on those check out the IR-book
This package helps you query indexes of this form, in fairly efficient way, keep in mind it expects the []int32 slices to be sorted. Example:
package main
import (
"fmt"
"github.com/rekki/go-query"
)
func main() {
totalDocumentsInIndex := 10
q := query.And(
query.Or(
query.Term(totalDocumentsInIndex, "a", []int32{1, 2, 8, 9}),
query.Term(totalDocumentsInIndex, "b", []int32{3, 9, 8}),
),
query.AndNot(
query.Or(
query.Term(totalDocumentsInIndex, "c", []int32{4, 5}),
query.Term(totalDocumentsInIndex, "c", []int32{4, 100}),
),
query.Or(
query.Term(totalDocumentsInIndex, "d", []int32{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}),
query.Term(totalDocumentsInIndex, "e", []int32{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}),
),
),
)
// q.String() is {{a OR b} AND {{d OR e} -({c OR x})}}
for q.Next() != query.NO_MORE {
did := q.GetDocId()
score := q.Score()
fmt.Printf("matching %d, score: %f\n", did, score)
}
}will print:
matching 1, score: 2.639057
matching 2, score: 2.639057
matching 3, score: 2.852632
matching 8, score: 2.639057
matching 9, score: 4.105394