mirror of
https://github.com/savaki/jq
synced 2020-06-03 18:33:18 +00:00
83 lines
1.8 KiB
Go
83 lines
1.8 KiB
Go
// Copyright (c) 2016 Matt Ho <matt.ho@gmail.com>
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package jq
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import (
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"fmt"
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"regexp"
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"strconv"
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"strings"
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)
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var (
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reArray = regexp.MustCompile(`^\s*\[\s*(\d+)(\s*:\s*(\d+))?\s*]\s*$`)
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)
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// Must is a convenience method similar to template.Must
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func Must(op Op, err error) Op {
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if err != nil {
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panic(fmt.Errorf("unable to parse selector; %v", err.Error()))
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}
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return op
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}
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// Parse takes a string representation of a selector and returns the corresponding Op definition
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func Parse(selector string) (Op, error) {
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segments := strings.Split(selector, ".")
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ops := make([]Op, 0, len(segments))
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for _, segment := range segments {
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key := strings.TrimSpace(segment)
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if key == "" {
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continue
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}
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if op, ok := parseArray(key); ok {
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ops = append(ops, op)
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continue
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}
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ops = append(ops, Dot(key))
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}
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return Chain(ops...), nil
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}
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func parseArray(key string) (Op, bool) {
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match := reArray.FindAllStringSubmatch(key, -1)
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if len(match) != 1 {
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return nil, false
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}
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fromStr := match[0][1]
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from, err := strconv.Atoi(fromStr)
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if err != nil {
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return nil, false
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}
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toStr := match[0][3]
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if toStr == "" {
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return Index(from), true
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}
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to, err := strconv.Atoi(toStr)
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if err != nil {
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return nil, false
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}
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return Range(from, to), true
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}
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