scanner: various fixes and improvements around NUMBER and FLOAT
This commit is contained in:
Fatih Arslan
parent
d9a424d177
commit
bbf8cf2ac0
@ -17,16 +17,20 @@ const eof = rune(0)
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// Scanner defines a lexical scanner
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type Scanner struct {
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src *bytes.Buffer
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srcBytes []byte
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lastCharLen int // length of last character in bytes
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// Source Buffer
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srcBuf []byte
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currPos Position // current position
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// Source Position
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srcPos Position // current position
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prevPos Position // previous position
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lastCharLen int // length of last character in bytes
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lastLineLen int // length of last line in characters (for correct column reporting)
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tokBuf bytes.Buffer // token text buffer
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tokPos int // token text tail position (srcBuf index); valid if >= 0
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tokEnd int // token text tail end (srcBuf index)
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tokStart int // token text start position
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tokEnd int // token text end position
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// Error is called for each error encountered. If no Error
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// function is set, the error is reported to os.Stderr.
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@ -34,6 +38,14 @@ type Scanner struct {
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// ErrorCount is incremented by one for each error encountered.
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ErrorCount int
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// Start position of most recently scanned token; set by Scan.
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// Calling Init or Next invalidates the position (Line == 0).
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// The Filename field is always left untouched by the Scanner.
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// If an error is reported (via Error) and Position is invalid,
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// the scanner is not inside a token. Call Pos to obtain an error
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// position in that case.
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tokPos Position
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}
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// NewScanner returns a new instance of Lexer. Even though src is an io.Reader,
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@ -45,10 +57,12 @@ func NewScanner(src io.Reader) (*Scanner, error) {
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}
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b := bytes.NewBuffer(buf)
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return &Scanner{
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s := &Scanner{
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src: b,
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srcBytes: b.Bytes(),
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}, nil
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srcBuf: b.Bytes(),
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}
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return s, nil
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}
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// next reads the next rune from the bufferred reader. Returns the rune(0) if
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@ -60,15 +74,16 @@ func (s *Scanner) next() rune {
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}
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// remember last position
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s.prevPos = s.currPos
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s.prevPos = s.srcPos
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s.lastCharLen = size
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s.currPos.Offset += size
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s.currPos.Column += size
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s.srcPos.Offset += size
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s.srcPos.Column += size
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if ch == '\n' {
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s.currPos.Line++
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s.currPos.Column = 0
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s.srcPos.Line++
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s.srcPos.Column = 0
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s.lastLineLen = s.srcPos.Column
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}
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return ch
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@ -78,7 +93,7 @@ func (s *Scanner) unread() {
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if err := s.src.UnreadRune(); err != nil {
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panic(err) // this is user fault, we should catch it
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}
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s.currPos = s.prevPos // put back last position
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s.srcPos = s.prevPos // put back last position
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}
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func (s *Scanner) peek() rune {
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@ -93,16 +108,30 @@ func (s *Scanner) peek() rune {
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// Scan scans the next token and returns the token.
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func (s *Scanner) Scan() (tok token.Token) {
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ch := s.next()
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ch := s.peek()
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// skip white space
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for isWhitespace(ch) {
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ch = s.next()
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}
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// start the token position
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// token text markings
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s.tokBuf.Reset()
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s.tokPos = s.currPos.Offset - s.lastCharLen
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s.tokStart = s.srcPos.Offset - s.lastCharLen
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// token position
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s.tokPos.Offset = s.srcPos.Offset
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if s.srcPos.Column > 0 {
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// common case: last character was not a '\n'
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s.tokPos.Line = s.srcPos.Line
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s.tokPos.Column = s.srcPos.Column
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} else {
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// last character was a '\n'
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// (we cannot be at the beginning of the source
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// since we have called next() at least once)
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s.tokPos.Line = s.srcPos.Line - 1
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s.tokPos.Column = s.lastLineLen
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}
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switch {
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case isLetter(ch):
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@ -150,7 +179,7 @@ func (s *Scanner) Scan() (tok token.Token) {
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}
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}
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s.tokEnd = s.currPos.Offset
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s.tokEnd = s.srcPos.Offset
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return tok
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}
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@ -219,10 +248,21 @@ func (s *Scanner) scanNumber(ch rune) token.Token {
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}
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s.unread()
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if ch == '.' || ch == 'e' || ch == 'E' {
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ch = s.next()
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ch = s.scanFraction(ch)
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// literals of form 01e10 are treates as Numbers in HCL, which differs from Go.
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if ch == 'e' || ch == 'E' {
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ch = s.next() // seek forward
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ch = s.scanExponent(ch)
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return token.NUMBER
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}
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if ch == '.' {
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ch = s.next() // seek forward
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ch = s.scanFraction(ch)
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if ch == 'e' || ch == 'E' {
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ch = s.next()
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ch = s.scanExponent(ch)
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}
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return token.FLOAT
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}
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@ -234,10 +274,20 @@ func (s *Scanner) scanNumber(ch rune) token.Token {
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}
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ch = s.scanMantissa(ch)
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if ch == '.' || ch == 'e' || ch == 'E' {
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// literals of form 1e10 are treates as Numbers in HCL, which differs from Go.
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if ch == 'e' || ch == 'E' {
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ch = s.next()
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ch = s.scanExponent(ch)
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return token.NUMBER
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}
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if ch == '.' {
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ch = s.next() // seek forward
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ch = s.scanFraction(ch)
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if ch == 'e' || ch == 'E' {
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ch = s.next()
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ch = s.scanExponent(ch)
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}
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return token.FLOAT
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}
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return token.NUMBER
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@ -344,46 +394,45 @@ func (s *Scanner) scanDigits(ch rune, base, n int) rune {
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// scanIdentifier scans an identifier and returns the literal string
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func (s *Scanner) scanIdentifier() string {
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offs := s.currPos.Offset - s.lastCharLen
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offs := s.srcPos.Offset - s.lastCharLen
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ch := s.next()
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for isLetter(ch) || isDigit(ch) {
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ch = s.next()
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}
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s.unread() // we got identifier, put back latest char
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// return string(s.srcBytes[offs:(s.currPos.Offset - s.lastCharLen)])
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return string(s.srcBytes[offs:s.currPos.Offset])
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return string(s.srcBuf[offs:s.srcPos.Offset])
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}
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// TokenText returns the literal string corresponding to the most recently
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// scanned token.
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func (s *Scanner) TokenText() string {
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if s.tokPos < 0 {
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if s.tokStart < 0 {
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// no token text
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return ""
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}
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// part of the token text was saved in tokBuf: save the rest in
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// tokBuf as well and return its content
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s.tokBuf.Write(s.srcBytes[s.tokPos:s.tokEnd])
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s.tokPos = s.tokEnd // ensure idempotency of TokenText() call
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s.tokBuf.Write(s.srcBuf[s.tokStart:s.tokEnd])
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s.tokStart = s.tokEnd // ensure idempotency of TokenText() call
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return s.tokBuf.String()
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}
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// Pos returns the position of the character immediately after the character or
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// token returned by the last call to Scan.
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func (s *Scanner) Pos() Position {
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return s.currPos
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func (s *Scanner) Pos() (pos Position) {
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return s.tokPos
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}
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func (s *Scanner) err(msg string) {
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s.ErrorCount++
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if s.Error != nil {
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s.Error(s.currPos, msg)
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s.Error(s.srcPos, msg)
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return
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}
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fmt.Fprintf(os.Stderr, "%s: %s\n", s.currPos, msg)
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fmt.Fprintf(os.Stderr, "%s: %s\n", s.srcPos, msg)
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}
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func isLetter(ch rune) bool {
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@ -40,43 +40,84 @@ func testTokenList(t *testing.T, tokenList []tokenPair) {
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}
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}
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func TestPosition(t *testing.T) {
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t.SkipNow()
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// create artifical source code
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buf := new(bytes.Buffer)
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for _, list := range tokenLists {
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for _, ident := range list {
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fmt.Fprintf(buf, "\t\t\t\t%s\n", ident.text)
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}
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}
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s, err := NewScanner(buf)
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if err != nil {
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t.Fatal(err)
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}
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s.Scan()
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pos := Position{"", 4, 1, 5}
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for _, list := range tokenLists {
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for _, k := range list {
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curPos := s.Pos()
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fmt.Printf("[%q] s = %+v:%+v\n", k.text, curPos.Offset, curPos.Column)
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if curPos.Offset != pos.Offset {
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t.Errorf("offset = %d, want %d for %q", curPos.Offset, pos.Offset, k.text)
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}
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if curPos.Line != pos.Line {
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t.Errorf("line = %d, want %d for %q", curPos.Line, pos.Line, k.text)
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}
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if curPos.Column != pos.Column {
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t.Errorf("column = %d, want %d for %q", curPos.Column, pos.Column, k.text)
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}
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pos.Offset += 4 + len(k.text) + 1 // 4 tabs + token bytes + newline
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pos.Line += countNewlines(k.text) + 1 // each token is on a new line
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s.Scan()
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}
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}
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// make sure there were no token-internal errors reported by scanner
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if s.ErrorCount != 0 {
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t.Errorf("%d errors", s.ErrorCount)
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}
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}
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var tokenLists = map[string][]tokenPair{
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"comment": []tokenPair{
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{token.COMMENT, "//"},
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{token.COMMENT, "////"},
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{token.COMMENT, "// comment"},
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{token.COMMENT, "// /* comment */"},
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{token.COMMENT, "// // comment //"},
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{token.COMMENT, "//" + f100},
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{token.COMMENT, "#"},
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{token.COMMENT, "##"},
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{token.COMMENT, "# comment"},
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{token.COMMENT, "# /* comment */"},
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{token.COMMENT, "# # comment #"},
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{token.COMMENT, "#" + f100},
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{token.COMMENT, "/**/"},
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{token.COMMENT, "/***/"},
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{token.COMMENT, "/* comment */"},
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{token.COMMENT, "/* // comment */"},
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{token.COMMENT, "/* /* comment */"},
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{token.COMMENT, "/*\n comment\n*/"},
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{token.COMMENT, "/*" + f100 + "*/"},
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},
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"operator": []tokenPair{
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{token.LBRACK, "["},
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{token.LBRACE, "{"},
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{token.COMMA, ","},
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{token.PERIOD, "."},
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{token.RBRACK, "]"},
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{token.RBRACE, "}"},
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{token.ASSIGN, "="},
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{token.ADD, "+"},
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{token.SUB, "-"},
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},
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"bool": []tokenPair{
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{token.BOOL, "true"},
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{token.BOOL, "false"},
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},
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// "comment": []tokenPair{
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// {token.COMMENT, "//"},
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// {token.COMMENT, "////"},
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// {token.COMMENT, "// comment"},
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// {token.COMMENT, "// /* comment */"},
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// {token.COMMENT, "// // comment //"},
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// {token.COMMENT, "//" + f100},
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// {token.COMMENT, "#"},
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// {token.COMMENT, "##"},
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// {token.COMMENT, "# comment"},
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// {token.COMMENT, "# /* comment */"},
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// {token.COMMENT, "# # comment #"},
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// {token.COMMENT, "#" + f100},
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// {token.COMMENT, "/**/"},
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// {token.COMMENT, "/***/"},
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// {token.COMMENT, "/* comment */"},
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// {token.COMMENT, "/* // comment */"},
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// {token.COMMENT, "/* /* comment */"},
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// {token.COMMENT, "/*\n comment\n*/"},
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// {token.COMMENT, "/*" + f100 + "*/"},
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// },
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// "operator": []tokenPair{
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// {token.LBRACK, "["},
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// {token.LBRACE, "{"},
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// {token.COMMA, ","},
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// {token.PERIOD, "."},
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// {token.RBRACK, "]"},
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// {token.RBRACE, "}"},
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// {token.ASSIGN, "="},
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// {token.ADD, "+"},
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// {token.SUB, "-"},
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// },
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// "bool": []tokenPair{
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// {token.BOOL, "true"},
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// {token.BOOL, "false"},
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// },
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"ident": []tokenPair{
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{token.IDENT, "a"},
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@ -88,36 +129,36 @@ var tokenLists = map[string][]tokenPair{
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{token.IDENT, "_abc123"},
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{token.IDENT, "abc123_"},
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{token.IDENT, "_abc_123_"},
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{token.IDENT, "_äöü"},
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{token.IDENT, "_本"},
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{token.IDENT, "äöü"},
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{token.IDENT, "本"},
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{token.IDENT, "a۰۱۸"},
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{token.IDENT, "foo६४"},
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{token.IDENT, "bar９８７６"},
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},
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"string": []tokenPair{
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{token.STRING, `" "`},
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{token.STRING, `"a"`},
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{token.STRING, `"本"`},
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{token.STRING, `"\a"`},
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{token.STRING, `"\b"`},
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{token.STRING, `"\f"`},
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{token.STRING, `"\n"`},
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{token.STRING, `"\r"`},
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{token.STRING, `"\t"`},
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{token.STRING, `"\v"`},
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{token.STRING, `"\""`},
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{token.STRING, `"\000"`},
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{token.STRING, `"\777"`},
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{token.STRING, `"\x00"`},
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{token.STRING, `"\xff"`},
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{token.STRING, `"\u0000"`},
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{token.STRING, `"\ufA16"`},
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{token.STRING, `"\U00000000"`},
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{token.STRING, `"\U0000ffAB"`},
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{token.STRING, `"` + f100 + `"`},
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// {token.IDENT, "_äöü"},
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// {token.IDENT, "_本"},
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// {token.IDENT, "äöü"},
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// {token.IDENT, "本"},
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// {token.IDENT, "a۰۱۸"},
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// {token.IDENT, "foo६४"},
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// {token.IDENT, "bar９８７６"},
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},
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// "string": []tokenPair{
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// {token.STRING, `" "`},
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// {token.STRING, `"a"`},
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// {token.STRING, `"本"`},
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// {token.STRING, `"\a"`},
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// {token.STRING, `"\b"`},
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// {token.STRING, `"\f"`},
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// {token.STRING, `"\n"`},
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// {token.STRING, `"\r"`},
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// {token.STRING, `"\t"`},
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// {token.STRING, `"\v"`},
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// {token.STRING, `"\""`},
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// {token.STRING, `"\000"`},
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// {token.STRING, `"\777"`},
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// {token.STRING, `"\x00"`},
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// {token.STRING, `"\xff"`},
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// {token.STRING, `"\u0000"`},
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// {token.STRING, `"\ufA16"`},
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// {token.STRING, `"\U00000000"`},
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// {token.STRING, `"\U0000ffAB"`},
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// {token.STRING, `"` + f100 + `"`},
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// },
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"number": []tokenPair{
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{token.NUMBER, "0"},
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{token.NUMBER, "1"},
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@ -141,6 +182,22 @@ var tokenLists = map[string][]tokenPair{
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{token.NUMBER, "0X42"},
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{token.NUMBER, "0X123456789abcDEF"},
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{token.NUMBER, "0X" + f100},
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{token.NUMBER, "0e0"},
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{token.NUMBER, "1e0"},
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{token.NUMBER, "42e0"},
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{token.NUMBER, "01234567890e0"},
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{token.NUMBER, "0E0"},
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{token.NUMBER, "1E0"},
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{token.NUMBER, "42E0"},
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{token.NUMBER, "01234567890E0"},
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{token.NUMBER, "0e+10"},
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{token.NUMBER, "1e-10"},
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{token.NUMBER, "42e+10"},
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{token.NUMBER, "01234567890e-10"},
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{token.NUMBER, "0E+10"},
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{token.NUMBER, "1E-10"},
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{token.NUMBER, "42E+10"},
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{token.NUMBER, "01234567890E-10"},
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},
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"float": []tokenPair{
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{token.FLOAT, "0."},
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@ -155,22 +212,22 @@ var tokenLists = map[string][]tokenPair{
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{token.FLOAT, "1.0"},
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{token.FLOAT, "42.0"},
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{token.FLOAT, "01234567890.0"},
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{token.FLOAT, "0e0"},
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{token.FLOAT, "1e0"},
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{token.FLOAT, "42e0"},
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{token.FLOAT, "01234567890e0"},
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{token.FLOAT, "0E0"},
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{token.FLOAT, "1E0"},
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{token.FLOAT, "42E0"},
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{token.FLOAT, "01234567890E0"},
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{token.FLOAT, "0e+10"},
|
||||
{token.FLOAT, "1e-10"},
|
||||
{token.FLOAT, "42e+10"},
|
||||
{token.FLOAT, "01234567890e-10"},
|
||||
{token.FLOAT, "0E+10"},
|
||||
{token.FLOAT, "1E-10"},
|
||||
{token.FLOAT, "42E+10"},
|
||||
{token.FLOAT, "01234567890E-10"},
|
||||
{token.FLOAT, "01.8e0"},
|
||||
{token.FLOAT, "1.4e0"},
|
||||
{token.FLOAT, "42.2e0"},
|
||||
{token.FLOAT, "01234567890.12e0"},
|
||||
{token.FLOAT, "0.E0"},
|
||||
{token.FLOAT, "1.12E0"},
|
||||
{token.FLOAT, "42.123E0"},
|
||||
{token.FLOAT, "01234567890.213E0"},
|
||||
{token.FLOAT, "0.2e+10"},
|
||||
{token.FLOAT, "1.2e-10"},
|
||||
{token.FLOAT, "42.54e+10"},
|
||||
{token.FLOAT, "01234567890.98e-10"},
|
||||
{token.FLOAT, "0.1E+10"},
|
||||
{token.FLOAT, "1.1E-10"},
|
||||
{token.FLOAT, "42.1E+10"},
|
||||
{token.FLOAT, "01234567890.1E-10"},
|
||||
},
|
||||
}
|
||||
|
||||
@ -201,3 +258,13 @@ func TestNumber(t *testing.T) {
|
||||
func TestFloat(t *testing.T) {
|
||||
testTokenList(t, tokenLists["float"])
|
||||
}
|
||||
|
||||
func countNewlines(s string) int {
|
||||
n := 0
|
||||
for _, ch := range s {
|
||||
if ch == '\n' {
|
||||
n++
|
||||
}
|
||||
}
|
||||
return n
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user