96 lines
1.7 KiB
Go
96 lines
1.7 KiB
Go
package emdbed
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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 endline = regexp.MustCompile(`(?m)$`)
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type emdbed struct {
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name string
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contents string
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language string
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start string
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end string
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}
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func (e emdbed) line(line int, end bool) (int, error) {
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if line == 1 && !end {
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return 0, nil
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}
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indexes := endline.FindAllStringIndex(e.contents, -1)
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if len(indexes) < line {
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return 0, fmt.Errorf("file %q has no line %d", e.name, line)
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}
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dec := 1
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if !end {
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dec++
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}
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var inc int
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if !end {
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inc++
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}
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return indexes[line-dec][0] + inc, nil
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}
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func (e emdbed) regex(pattern string, end bool) (int, error) {
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re, err := regexp.Compile(pattern)
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if err != nil {
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return 0, err
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}
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match := re.FindStringIndex(e.contents)
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if match == nil {
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return 0, fmt.Errorf("file %q has no match for pattern %q", e.name, pattern)
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}
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var inc int
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if end {
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inc++
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}
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return match[0] + inc, nil
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}
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func (e emdbed) selector(selector string, end bool) (int, error) {
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switch {
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case strings.HasPrefix(selector, "L"):
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line, err := strconv.Atoi(selector[1:])
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if err != nil {
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return 0, err
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}
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return e.line(line, end)
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case strings.HasPrefix(selector, "/"):
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pattern := strings.Trim(selector, "/")
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return e.regex(pattern, end)
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default:
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return 0, fmt.Errorf("unknown selector %q", selector)
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}
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}
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func (e emdbed) Start() (int, error) {
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if e.start == "" {
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return 0, nil
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}
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return e.selector(e.start, false)
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}
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func (e emdbed) End() (int, error) {
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if e.end == "" {
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return len(e.contents), nil
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}
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return e.selector(e.end, true)
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}
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func (e emdbed) Selection() (string, error) {
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start, err := e.Start()
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if err != nil {
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return "", err
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}
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end, err := e.End()
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if err != nil {
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return "", err
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}
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return e.contents[start:end], nil
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}
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