501 lines
10 KiB
Go
501 lines
10 KiB
Go
package parser
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import (
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"bufio"
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"container/list"
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"fmt"
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"io"
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"regexp"
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)
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const (
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tokEOF = -(iota + 1)
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tokDoctype
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tokComment
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tokIndent
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tokOutdent
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tokBlank
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tokId
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tokClassName
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tokTag
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tokText
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tokAttribute
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tokIf
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tokElse
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tokEach
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tokAssignment
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tokImport
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tokNamedBlock
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tokExtends
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tokMixin
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tokMixinCall
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)
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const (
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scnNewLine = iota
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scnLine
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scnEOF
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)
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type scanner struct {
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reader *bufio.Reader
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indentStack *list.List
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stash *list.List
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state int32
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buffer string
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line int
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col int
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lastTokenLine int
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lastTokenCol int
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lastTokenSize int
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readRaw bool
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}
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type token struct {
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Kind rune
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Value string
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Data map[string]string
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}
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func newScanner(r io.Reader) *scanner {
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s := new(scanner)
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s.reader = bufio.NewReader(r)
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s.indentStack = list.New()
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s.stash = list.New()
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s.state = scnNewLine
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s.line = -1
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s.col = 0
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return s
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}
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func (s *scanner) Pos() SourcePosition {
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return SourcePosition{s.lastTokenLine + 1, s.lastTokenCol + 1, s.lastTokenSize, ""}
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}
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// Returns next token found in buffer
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func (s *scanner) Next() *token {
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if s.readRaw {
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s.readRaw = false
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return s.NextRaw()
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}
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s.ensureBuffer()
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if stashed := s.stash.Front(); stashed != nil {
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tok := stashed.Value.(*token)
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s.stash.Remove(stashed)
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return tok
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}
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switch s.state {
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case scnEOF:
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if outdent := s.indentStack.Back(); outdent != nil {
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s.indentStack.Remove(outdent)
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return &token{tokOutdent, "", nil}
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}
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return &token{tokEOF, "", nil}
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case scnNewLine:
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s.state = scnLine
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if tok := s.scanIndent(); tok != nil {
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return tok
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}
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return s.Next()
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case scnLine:
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if tok := s.scanMixin(); tok != nil {
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return tok
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}
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if tok := s.scanMixinCall(); tok != nil {
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return tok
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}
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if tok := s.scanDoctype(); tok != nil {
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return tok
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}
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if tok := s.scanCondition(); tok != nil {
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return tok
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}
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if tok := s.scanEach(); tok != nil {
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return tok
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}
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if tok := s.scanImport(); tok != nil {
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return tok
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}
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if tok := s.scanExtends(); tok != nil {
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return tok
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}
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if tok := s.scanBlock(); tok != nil {
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return tok
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}
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if tok := s.scanAssignment(); tok != nil {
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return tok
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}
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if tok := s.scanTag(); tok != nil {
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return tok
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}
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if tok := s.scanId(); tok != nil {
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return tok
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}
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if tok := s.scanClassName(); tok != nil {
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return tok
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}
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if tok := s.scanAttribute(); tok != nil {
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return tok
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}
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if tok := s.scanComment(); tok != nil {
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return tok
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}
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if tok := s.scanText(); tok != nil {
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return tok
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}
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}
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return nil
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}
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func (s *scanner) NextRaw() *token {
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result := ""
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level := 0
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for {
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s.ensureBuffer()
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switch s.state {
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case scnEOF:
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return &token{tokText, result, map[string]string{"Mode": "raw"}}
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case scnNewLine:
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s.state = scnLine
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if tok := s.scanIndent(); tok != nil {
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if tok.Kind == tokIndent {
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level++
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} else if tok.Kind == tokOutdent {
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level--
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} else {
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result = result + "\n"
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continue
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}
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if level < 0 {
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s.stash.PushBack(&token{tokOutdent, "", nil})
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if len(result) > 0 && result[len(result)-1] == '\n' {
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result = result[:len(result)-1]
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}
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return &token{tokText, result, map[string]string{"Mode": "raw"}}
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}
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}
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case scnLine:
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if len(result) > 0 {
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result = result + "\n"
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}
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for i := 0; i < level; i++ {
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result += "\t"
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}
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result = result + s.buffer
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s.consume(len(s.buffer))
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}
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}
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return nil
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}
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var rgxIndent = regexp.MustCompile(`^(\s+)`)
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func (s *scanner) scanIndent() *token {
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if len(s.buffer) == 0 {
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return &token{tokBlank, "", nil}
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}
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var head *list.Element
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for head = s.indentStack.Front(); head != nil; head = head.Next() {
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value := head.Value.(*regexp.Regexp)
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if match := value.FindString(s.buffer); len(match) != 0 {
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s.consume(len(match))
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} else {
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break
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}
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}
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newIndent := rgxIndent.FindString(s.buffer)
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if len(newIndent) != 0 && head == nil {
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s.indentStack.PushBack(regexp.MustCompile(regexp.QuoteMeta(newIndent)))
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s.consume(len(newIndent))
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return &token{tokIndent, newIndent, nil}
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}
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if len(newIndent) == 0 && head != nil {
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for head != nil {
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next := head.Next()
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s.indentStack.Remove(head)
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if next == nil {
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return &token{tokOutdent, "", nil}
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} else {
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s.stash.PushBack(&token{tokOutdent, "", nil})
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}
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head = next
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}
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}
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if len(newIndent) != 0 && head != nil {
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panic("Mismatching indentation. Please use a coherent indent schema.")
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}
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return nil
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}
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var rgxDoctype = regexp.MustCompile(`^(!!!|doctype)\s*(.*)`)
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func (s *scanner) scanDoctype() *token {
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if sm := rgxDoctype.FindStringSubmatch(s.buffer); len(sm) != 0 {
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if len(sm[2]) == 0 {
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sm[2] = "html"
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}
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s.consume(len(sm[0]))
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return &token{tokDoctype, sm[2], nil}
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}
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return nil
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}
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var rgxIf = regexp.MustCompile(`^if\s+(.+)$`)
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var rgxElse = regexp.MustCompile(`^else\s*`)
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func (s *scanner) scanCondition() *token {
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if sm := rgxIf.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokIf, sm[1], nil}
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}
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if sm := rgxElse.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokElse, "", nil}
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}
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return nil
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}
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var rgxEach = regexp.MustCompile(`^each\s+(\$[\w0-9\-_]*)(?:\s*,\s*(\$[\w0-9\-_]*))?\s+in\s+(.+)$`)
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func (s *scanner) scanEach() *token {
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if sm := rgxEach.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokEach, sm[3], map[string]string{"X": sm[1], "Y": sm[2]}}
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}
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return nil
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}
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var rgxAssignment = regexp.MustCompile(`^(\$[\w0-9\-_]*)?\s*=\s*(.+)$`)
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func (s *scanner) scanAssignment() *token {
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if sm := rgxAssignment.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokAssignment, sm[2], map[string]string{"X": sm[1]}}
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}
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return nil
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}
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var rgxComment = regexp.MustCompile(`^\/\/(-)?\s*(.*)$`)
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func (s *scanner) scanComment() *token {
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if sm := rgxComment.FindStringSubmatch(s.buffer); len(sm) != 0 {
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mode := "embed"
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if len(sm[1]) != 0 {
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mode = "silent"
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}
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s.consume(len(sm[0]))
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return &token{tokComment, sm[2], map[string]string{"Mode": mode}}
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}
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return nil
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}
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var rgxId = regexp.MustCompile(`^#([\w-]+)(?:\s*\?\s*(.*)$)?`)
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func (s *scanner) scanId() *token {
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if sm := rgxId.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokId, sm[1], map[string]string{"Condition": sm[2]}}
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}
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return nil
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}
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var rgxClassName = regexp.MustCompile(`^\.([\w-]+)(?:\s*\?\s*(.*)$)?`)
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func (s *scanner) scanClassName() *token {
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if sm := rgxClassName.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokClassName, sm[1], map[string]string{"Condition": sm[2]}}
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}
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return nil
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}
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var rgxAttribute = regexp.MustCompile(`^\[([\w\-]+)\s*(?:=\s*(\"([^\"\\]*)\"|([^\]]+)))?\](?:\s*\?\s*(.*)$)?`)
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func (s *scanner) scanAttribute() *token {
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if sm := rgxAttribute.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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if len(sm[3]) != 0 || sm[2] == "" {
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return &token{tokAttribute, sm[1], map[string]string{"Content": sm[3], "Mode": "raw", "Condition": sm[5]}}
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}
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return &token{tokAttribute, sm[1], map[string]string{"Content": sm[4], "Mode": "expression", "Condition": sm[5]}}
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}
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return nil
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}
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var rgxImport = regexp.MustCompile(`^import\s+([0-9a-zA-Z_\-\. \/]*)$`)
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func (s *scanner) scanImport() *token {
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if sm := rgxImport.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokImport, sm[1], nil}
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}
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return nil
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}
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var rgxExtends = regexp.MustCompile(`^extends\s+([0-9a-zA-Z_\-\. \/]*)$`)
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func (s *scanner) scanExtends() *token {
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if sm := rgxExtends.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokExtends, sm[1], nil}
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}
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return nil
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}
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var rgxBlock = regexp.MustCompile(`^block\s+(?:(append|prepend)\s+)?([0-9a-zA-Z_\-\. \/]*)$`)
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func (s *scanner) scanBlock() *token {
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if sm := rgxBlock.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokNamedBlock, sm[2], map[string]string{"Modifier": sm[1]}}
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}
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return nil
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}
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var rgxTag = regexp.MustCompile(`^(\w[-:\w]*)`)
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func (s *scanner) scanTag() *token {
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if sm := rgxTag.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokTag, sm[1], nil}
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}
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return nil
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}
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var rgxMixin = regexp.MustCompile(`^mixin ([a-zA-Z_]+\w*)(\(((\$\w*(,\s)?)*)\))?$`)
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func (s *scanner) scanMixin() *token {
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if sm := rgxMixin.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokMixin, sm[1], map[string]string{"Args": sm[3]}}
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}
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return nil
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}
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var rgxMixinCall = regexp.MustCompile(`^\+([A-Za-z_]+\w*)(\((.+(,\s)?)*\))?$`)
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func (s *scanner) scanMixinCall() *token {
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if sm := rgxMixinCall.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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return &token{tokMixinCall, sm[1], map[string]string{"Args": sm[3]}}
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}
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return nil
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}
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var rgxText = regexp.MustCompile(`^(\|)? ?(.*)$`)
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func (s *scanner) scanText() *token {
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if sm := rgxText.FindStringSubmatch(s.buffer); len(sm) != 0 {
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s.consume(len(sm[0]))
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mode := "inline"
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if sm[1] == "|" {
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mode = "piped"
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}
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return &token{tokText, sm[2], map[string]string{"Mode": mode}}
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}
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return nil
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}
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// Moves position forward, and removes beginning of s.buffer (len bytes)
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func (s *scanner) consume(runes int) {
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if len(s.buffer) < runes {
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panic(fmt.Sprintf("Unable to consume %d runes from buffer.", runes))
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}
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s.lastTokenLine = s.line
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s.lastTokenCol = s.col
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s.lastTokenSize = runes
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s.buffer = s.buffer[runes:]
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s.col += runes
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}
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// Reads string into s.buffer
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func (s *scanner) ensureBuffer() {
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if len(s.buffer) > 0 {
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return
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}
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buf, err := s.reader.ReadString('\n')
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if err != nil && err != io.EOF {
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panic(err)
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} else if err != nil && len(buf) == 0 {
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s.state = scnEOF
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} else {
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// endline "LF only" or "\n" use Unix, Linux, modern MacOS X, FreeBSD, BeOS, RISC OS
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if buf[len(buf)-1] == '\n' {
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buf = buf[:len(buf)-1]
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}
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// endline "CR+LF" or "\r\n" use internet protocols, DEC RT-11, Windows, CP/M, MS-DOS, OS/2, Symbian OS
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if len(buf) > 0 && buf[len(buf)-1] == '\r' {
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buf = buf[:len(buf)-1]
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}
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s.state = scnNewLine
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s.buffer = buf
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s.line += 1
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s.col = 0
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}
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}
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