cayley/graph/sexp/session.go
kortschak d6f94be514 Base nexting on interface satisfaction
This is done unsubtlely at the moment and there is plenty of room for
optimisation of assertion location to prevent repeated reasserting as is
done now.
2014-07-30 16:06:46 +09:30

121 lines
2.5 KiB
Go

// Copyright 2014 The Cayley Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package sexp
// Defines a running session of the sexp query language.
import (
"errors"
"fmt"
"sort"
"github.com/google/cayley/graph"
)
type Session struct {
ts graph.TripleStore
debug bool
}
func NewSession(inputTripleStore graph.TripleStore) *Session {
var s Session
s.ts = inputTripleStore
return &s
}
func (s *Session) ToggleDebug() {
s.debug = !s.debug
}
func (s *Session) InputParses(input string) (graph.ParseResult, error) {
var parenDepth int
for i, x := range input {
if x == '(' {
parenDepth++
}
if x == ')' {
parenDepth--
if parenDepth < 0 {
min := 0
if (i - 10) > min {
min = i - 10
}
return graph.ParseFail, errors.New(fmt.Sprintf("Too many close parens at char %d: %s", i, input[min:i]))
}
}
}
if parenDepth > 0 {
return graph.ParseMore, nil
}
if len(ParseString(input)) > 0 {
return graph.Parsed, nil
}
return graph.ParseFail, errors.New("Invalid Syntax")
}
func (s *Session) ExecInput(input string, out chan interface{}, limit int) {
it := BuildIteratorTreeForQuery(s.ts, input)
newIt, changed := it.Optimize()
if changed {
it = newIt
}
if s.debug {
fmt.Println(it.DebugString(0))
}
nResults := 0
for {
_, ok := graph.Next(it)
if !ok {
break
}
tags := make(map[string]graph.Value)
it.TagResults(tags)
out <- &tags
nResults++
if nResults > limit && limit != -1 {
break
}
for it.NextResult() == true {
tags := make(map[string]graph.Value)
it.TagResults(tags)
out <- &tags
nResults++
if nResults > limit && limit != -1 {
break
}
}
}
close(out)
}
func (s *Session) ToText(result interface{}) string {
out := fmt.Sprintln("****")
tags := result.(map[string]graph.Value)
tagKeys := make([]string, len(tags))
i := 0
for k := range tags {
tagKeys[i] = k
i++
}
sort.Strings(tagKeys)
for _, k := range tagKeys {
if k == "$_" {
continue
}
out += fmt.Sprintf("%s : %s\n", k, s.ts.NameOf(tags[k]))
}
return out
}