featurebase/pql/parser.go

64 lines
1.5 KiB
Go

// Copyright 2017 Pilosa Corp.
//
// 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 pql
import (
"io"
"io/ioutil"
"strings"
"github.com/pkg/errors"
)
// TimeFormat is the go-style time format used to parse string dates.
const TimeFormat = "2006-01-02T15:04"
// Parser represents a parser for the PQL language.
type Parser struct {
r io.Reader
//scanner *bufScanner
PQL
}
// NewParser returns a new instance of Parser.
func NewParser(r io.Reader) *Parser {
return &Parser{
r: r,
// scanner: newBufScanner(r),
}
}
// ParseString parses s into a query.
func ParseString(s string) (*Query, error) {
return NewParser(strings.NewReader(s)).Parse()
}
// Parse parses the next node in the query.
func (p *Parser) Parse() (*Query, error) {
buf, err := ioutil.ReadAll(p.r)
if err != nil {
return nil, errors.Wrap(err, "reading buffer to parse")
}
p.PQL = PQL{
Buffer: string(buf),
}
p.Init()
err = p.PQL.Parse()
if err != nil {
return nil, errors.Wrap(err, "parsing")
}
p.Execute()
return &p.Query, nil
}