108 lines
1.9 KiB
Go
108 lines
1.9 KiB
Go
package goparsify
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import (
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"bytes"
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"unicode/utf8"
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)
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func StringLit(allowedQuotes string) Parser {
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return NewParser("string", func(ps *State) Node {
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ps.AutoWS()
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for i := 0; i < len(allowedQuotes); i++ {
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if ps.Input[ps.Pos] == allowedQuotes[i] {
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}
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}
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if !stringContainsByte(allowedQuotes, ps.Input[ps.Pos]) {
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ps.ErrorHere(allowedQuotes)
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return Node{}
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}
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quote := ps.Input[ps.Pos]
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var end int = ps.Pos + 1
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inputLen := len(ps.Input)
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var buf *bytes.Buffer
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for end < inputLen {
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switch ps.Input[end] {
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case '\\':
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if end+1 >= inputLen {
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ps.ErrorHere(string(quote))
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return Node{}
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}
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if buf == nil {
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buf = bytes.NewBufferString(ps.Input[ps.Pos+1 : end])
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}
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c := ps.Input[end+1]
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if c == 'u' {
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if end+6 >= inputLen {
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ps.Error.Expected = "[a-f0-9]{4}"
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ps.Error.pos = end + 2
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return Node{}
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}
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r, ok := unhex(ps.Input[end+2 : end+6])
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if !ok {
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ps.Error.Expected = "[a-f0-9]"
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ps.Error.pos = end + 2
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return Node{}
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}
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buf.WriteRune(r)
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end += 6
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} else {
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buf.WriteByte(c)
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end += 2
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}
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case quote:
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if buf == nil {
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result := ps.Input[ps.Pos+1 : end]
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ps.Pos = end + 1
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return Node{Token: result}
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}
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ps.Pos = end + 1
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return Node{Token: buf.String()}
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default:
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r, w := utf8.DecodeRuneInString(ps.Input[end:])
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end += w
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if buf != nil {
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buf.WriteRune(r)
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}
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}
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}
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ps.ErrorHere(string(quote))
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return Node{}
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})
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}
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func stringContainsByte(s string, b byte) bool {
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for i := 0; i < len(s); i++ {
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if b == s[i] {
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return true
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}
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}
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return false
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}
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func unhex(b string) (v rune, ok bool) {
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for _, c := range b {
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v <<= 4
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switch {
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case '0' <= c && c <= '9':
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v |= c - '0'
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case 'a' <= c && c <= 'f':
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v |= c - 'a' + 10
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case 'A' <= c && c <= 'F':
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v |= c - 'A' + 10
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default:
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return 0, false
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}
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}
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return v, true
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}
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