func readRune(r *bytes.Reader) rune {
n, s, err := r.ReadRune()
if n == _EOF_ || s == 0 || err != nil {
return _EOF_
}
return n
}
func render_line(line *bytes.Reader, h int) {
m_x, _ := termbox.Size()
for x := 0; x <= m_x; x++ {
if r, _, err := line.ReadRune(); err == nil {
termbox.SetCell(x, h, r, termbox.ColorBlack, termbox.ColorWhite)
} else {
termbox.SetCell(x, h, ' ', termbox.ColorBlack, termbox.ColorWhite)
}
}
}
func lex(program *bytes.Reader) (string, int) {
lexeme := make([]rune, 0, 128)
index := 0
//Get next Non-Whitespace Character
char, _, err := program.ReadRune()
for charClass(char) == WHITESPACE {
errCheck(err)
char, _, err = program.ReadRune()
}
switch charClass(char) {
case LETTER: //IDENT or KEYWORD
for ; charClass(char) == LETTER || charClass(char) == DIGIT; char, _, err = program.ReadRune() {
errCheck(err)
lexeme = lexeme[:index+1]
lexeme[index] = char
index++
}
program.UnreadRune()
result := string(lexeme)
return result, getKeyword(result)
case DIGIT:
for ; charClass(char) == DIGIT; char, _, err = program.ReadRune() {
errCheck(err)
lexeme = lexeme[:index+1]
lexeme[index] = char
index++
}
program.UnreadRune()
return string(lexeme), DIGIT
}
lexeme = lexeme[:index+1]
lexeme[index] = char
return string(lexeme), charClass(char)
}