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69 lines
1.4 KiB
69 lines
1.4 KiB
package scanner
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import (
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"bufio"
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"io"
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"github.com/brettlangdon/gython/errorcode"
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"github.com/brettlangdon/gython/token"
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)
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var EOF rune = 0
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var MAXINDENT int = 100
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type Scanner struct {
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state errorcode.ErrorCode
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reader *bufio.Reader
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currentPosition *Position
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positionBuffer []*Position
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currentLine int
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currentColumn int
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}
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func NewScanner(r io.Reader) *Scanner {
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return &Scanner{
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state: errorcode.E_OK,
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reader: bufio.NewReader(r),
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positionBuffer: make([]*Position, 0),
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currentLine: 1,
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currentColumn: 0,
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}
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}
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func (scanner *Scanner) nextPosition() *Position {
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if len(scanner.positionBuffer) > 0 {
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last = len(scanner.positionBuffer) - 1
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scanner.currentPosition = scanner.positionBuffer[last]
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scanner.positionBuffer = scanner.positionBuffer[0:last]
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return scanner.currentPosition
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}
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next, _, err := scanner.reader.ReadRune()
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if err != nil {
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scanner.state = errorcode.E_EOF
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next = EOF
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}
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scanner.currentColumn++
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if next == '\n' {
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scanner.currentLine++
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scanner.currentColumn = 0
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}
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return &Position{
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Char: next,
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Line: scanner.currentLine,
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Column: scanner.currentColumn,
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}
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}
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func (scanner *Scanner) unreadPosition(pos *Position) {
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scanner.positionBuffer = append(scanner.positionBuffer, pos)
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}
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func (scanner *Scanner) NextToken() *token.Token {
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return &Token{
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ID: token.ENDMARKER,
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}
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}
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