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@ -2,20 +2,56 @@ package sql
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import (
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"bufio"
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"bytes"
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"io"
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)
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type stack struct {
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c []rune
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}
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func newStack() *stack {
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return &stack{
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c: make([]rune, 0),
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}
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}
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func (s *stack) push(r rune) {
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s.c = append(s.c, r)
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}
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func (s *stack) pop() rune {
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if len(s.c) == 0 {
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return rune(0)
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}
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c := s.c[len(s.c)-1]
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s.c = s.c[:len(s.c)]
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return c
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}
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func (s *stack) peek() rune {
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if len(s.c) == 0 {
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return rune(0)
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}
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c := s.c[len(s.c)-1]
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return c
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}
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func (s *stack) empty() bool {
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return len(s.c) == 0
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}
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// Scanner represents a SQL statement scanner.
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type Scanner struct {
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r *bufio.Reader
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c []rune
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c *stack
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}
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// NewScanner returns a new instance of Scanner.
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func NewScanner(r io.Reader) *Scanner {
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return &Scanner{
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r: bufio.NewReader(r),
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c: make([]rune, 0),
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c: newStack(),
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}
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}
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@ -31,28 +67,39 @@ func (s *Scanner) read() rune {
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// Scan returns the next SQL statement.
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func (s *Scanner) Scan() string {
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var buf bytes.Buffer
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seekSemi := true
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for {
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if ch := s.read(); ch == eof {
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break
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} else if ch == '\'' {
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// Check for ' in c
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} else if !isLetter(ch) && !isDigit(ch) && ch != '_' {
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s.unread()
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ch := s.read()
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if ch == eof {
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break
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} else {
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}
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// Store the character.
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_, _ = buf.WriteRune(ch)
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if ch == '\'' || ch == '"' {
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if s.c.empty() {
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// add to stack
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seekSemi = false
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} else if s.c.peek() != ch {
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s.c.push(ch)
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seekSemi = false
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} else {
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s.c.pop()
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if s.c.empty() {
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seekSemi = true
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}
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}
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} else if ch == ';' && seekSemi {
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break
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}
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}
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// isWhitespace returns true if the rune is a space, tab, or newline.
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func isWhitespace(ch rune) bool { return ch == ' ' || ch == '\t' || ch == '\n' }
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// isLetter returns true if the rune is a letter.
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func isLetter(ch rune) bool { return (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') }
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// isDigit returns true if the rune is a digit.
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func isDigit(ch rune) bool { return (ch >= '0' && ch <= '9') }
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return buf.String()
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}
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// eof represents a marker rune for the end of the reader.
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var eof = rune(0)
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