88 lines
1.6 KiB
Go
88 lines
1.6 KiB
Go
package syntax
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import (
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"bytes"
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"errors"
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)
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type ReplacerData struct {
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Rep string
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Strings []string
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Rules []int
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}
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const (
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replaceSpecials = 4
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replaceLeftPortion = -1
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replaceRightPortion = -2
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replaceLastGroup = -3
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replaceWholeString = -4
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)
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//ErrReplacementError is a general error during parsing the replacement text
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var ErrReplacementError = errors.New("Replacement pattern error.")
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// NewReplacerData will populate a reusable replacer data struct based on the given replacement string
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// and the capture group data from a regexp
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func NewReplacerData(rep string, caps map[int]int, capsize int, capnames map[string]int, op RegexOptions) (*ReplacerData, error) {
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p := parser{
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options: op,
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caps: caps,
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capsize: capsize,
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capnames: capnames,
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}
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p.setPattern(rep)
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concat, err := p.scanReplacement()
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if err != nil {
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return nil, err
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}
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if concat.t != ntConcatenate {
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panic(ErrReplacementError)
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}
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sb := &bytes.Buffer{}
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var (
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strings []string
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rules []int
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)
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for _, child := range concat.children {
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switch child.t {
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case ntMulti:
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child.writeStrToBuf(sb)
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case ntOne:
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sb.WriteRune(child.ch)
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case ntRef:
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if sb.Len() > 0 {
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rules = append(rules, len(strings))
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strings = append(strings, sb.String())
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sb.Reset()
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}
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slot := child.m
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if len(caps) > 0 && slot >= 0 {
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slot = caps[slot]
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}
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rules = append(rules, -replaceSpecials-1-slot)
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default:
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panic(ErrReplacementError)
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}
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}
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if sb.Len() > 0 {
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rules = append(rules, len(strings))
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strings = append(strings, sb.String())
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}
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return &ReplacerData{
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Rep: rep,
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Strings: strings,
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Rules: rules,
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}, nil
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}
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