[nit.git] / src / parser / lexer.nit

# Lexer and its tokens.
# This file was generated by SableCC (http://www.sablecc.org/).
package lexer

intrude import parser_nodes
private import tables

redef class Token
    readable var _text: String

    fun parser_index: Int is abstract

    redef fun to_s: String do
        return "'{_text}'"
    end
end

redef class TEol
    redef fun parser_index: Int
    do
        return 0
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TComment
    redef fun parser_index: Int
    do
        return 1
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TKwmodule
    redef fun parser_index: Int
    do
        return 2
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TKwimport
    redef fun parser_index: Int
    do
        return 3
    end

    init init_tk(loc: Location)
    do
        _text = once "import"
                _location = loc
    end
end

redef class TKwclass
    redef fun parser_index: Int
    do
        return 4
    end

    init init_tk(loc: Location)
    do
        _text = once "class"
                _location = loc
    end
end

redef class TKwabstract
    redef fun parser_index: Int
    do
        return 5
    end

    init init_tk(loc: Location)
    do
        _text = once "abstract"
                _location = loc
    end
end

redef class TKwinterface
    redef fun parser_index: Int
    do
        return 6
    end

    init init_tk(loc: Location)
    do
        _text = once "interface"
                _location = loc
    end
end

redef class TKwuniversal
    redef fun parser_index: Int
    do
        return 7
    end

    init init_tk(loc: Location)
    do
        _text = once "universal"
                _location = loc
    end
end

redef class TKwspecial
    redef fun parser_index: Int
    do
        return 8
    end

    init init_tk(loc: Location)
    do
        _text = once "special"
                _location = loc
    end
end

redef class TKwend
    redef fun parser_index: Int
    do
        return 9
    end

    init init_tk(loc: Location)
    do
        _text = once "end"
                _location = loc
    end
end

redef class TKwmeth
    redef fun parser_index: Int
    do
        return 10
    end

    init init_tk(loc: Location)
    do
        _text = once "fun"
                _location = loc
    end
end

redef class TKwtype
    redef fun parser_index: Int
    do
        return 11
    end

    init init_tk(loc: Location)
    do
        _text = once "type"
                _location = loc
    end
end

redef class TKwinit
    redef fun parser_index: Int
    do
        return 12
    end

    init init_tk(loc: Location)
    do
        _text = once "init"
                _location = loc
    end
end

redef class TKwredef
    redef fun parser_index: Int
    do
        return 13
    end

    init init_tk(loc: Location)
    do
        _text = once "redef"
                _location = loc
    end
end

redef class TKwis
    redef fun parser_index: Int
    do
        return 14
    end

    init init_tk(loc: Location)
    do
        _text = once "is"
                _location = loc
    end
end

redef class TKwdo
    redef fun parser_index: Int
    do
        return 15
    end

    init init_tk(loc: Location)
    do
        _text = once "do"
                _location = loc
    end
end

redef class TKwreadable
    redef fun parser_index: Int
    do
        return 16
    end

    init init_tk(loc: Location)
    do
        _text = once "readable"
                _location = loc
    end
end

redef class TKwwritable
    redef fun parser_index: Int
    do
        return 17
    end

    init init_tk(loc: Location)
    do
        _text = once "writable"
                _location = loc
    end
end

redef class TKwvar
    redef fun parser_index: Int
    do
        return 18
    end

    init init_tk(loc: Location)
    do
        _text = once "var"
                _location = loc
    end
end

redef class TKwintern
    redef fun parser_index: Int
    do
        return 19
    end

    init init_tk(loc: Location)
    do
        _text = once "intern"
                _location = loc
    end
end

redef class TKwextern
    redef fun parser_index: Int
    do
        return 20
    end

    init init_tk(loc: Location)
    do
        _text = once "extern"
                _location = loc
    end
end

redef class TKwprotected
    redef fun parser_index: Int
    do
        return 21
    end

    init init_tk(loc: Location)
    do
        _text = once "protected"
                _location = loc
    end
end

redef class TKwprivate
    redef fun parser_index: Int
    do
        return 22
    end

    init init_tk(loc: Location)
    do
        _text = once "private"
                _location = loc
    end
end

redef class TKwintrude
    redef fun parser_index: Int
    do
        return 23
    end

    init init_tk(loc: Location)
    do
        _text = once "intrude"
                _location = loc
    end
end

redef class TKwif
    redef fun parser_index: Int
    do
        return 24
    end

    init init_tk(loc: Location)
    do
        _text = once "if"
                _location = loc
    end
end

redef class TKwthen
    redef fun parser_index: Int
    do
        return 25
    end

    init init_tk(loc: Location)
    do
        _text = once "then"
                _location = loc
    end
end

redef class TKwelse
    redef fun parser_index: Int
    do
        return 26
    end

    init init_tk(loc: Location)
    do
        _text = once "else"
                _location = loc
    end
end

redef class TKwwhile
    redef fun parser_index: Int
    do
        return 27
    end

    init init_tk(loc: Location)
    do
        _text = once "while"
                _location = loc
    end
end

redef class TKwloop
    redef fun parser_index: Int
    do
        return 28
    end

    init init_tk(loc: Location)
    do
        _text = once "loop"
                _location = loc
    end
end

redef class TKwfor
    redef fun parser_index: Int
    do
        return 29
    end

    init init_tk(loc: Location)
    do
        _text = once "for"
                _location = loc
    end
end

redef class TKwin
    redef fun parser_index: Int
    do
        return 30
    end

    init init_tk(loc: Location)
    do
        _text = once "in"
                _location = loc
    end
end

redef class TKwand
    redef fun parser_index: Int
    do
        return 31
    end

    init init_tk(loc: Location)
    do
        _text = once "and"
                _location = loc
    end
end

redef class TKwor
    redef fun parser_index: Int
    do
        return 32
    end

    init init_tk(loc: Location)
    do
        _text = once "or"
                _location = loc
    end
end

redef class TKwnot
    redef fun parser_index: Int
    do
        return 33
    end

    init init_tk(loc: Location)
    do
        _text = once "not"
                _location = loc
    end
end

redef class TKwreturn
    redef fun parser_index: Int
    do
        return 34
    end

    init init_tk(loc: Location)
    do
        _text = once "return"
                _location = loc
    end
end

redef class TKwcontinue
    redef fun parser_index: Int
    do
        return 35
    end

    init init_tk(loc: Location)
    do
        _text = once "continue"
                _location = loc
    end
end

redef class TKwbreak
    redef fun parser_index: Int
    do
        return 36
    end

    init init_tk(loc: Location)
    do
        _text = once "break"
                _location = loc
    end
end

redef class TKwabort
    redef fun parser_index: Int
    do
        return 37
    end

    init init_tk(loc: Location)
    do
        _text = once "abort"
                _location = loc
    end
end

redef class TKwassert
    redef fun parser_index: Int
    do
        return 38
    end

    init init_tk(loc: Location)
    do
        _text = once "assert"
                _location = loc
    end
end

redef class TKwnew
    redef fun parser_index: Int
    do
        return 39
    end

    init init_tk(loc: Location)
    do
        _text = once "new"
                _location = loc
    end
end

redef class TKwisa
    redef fun parser_index: Int
    do
        return 40
    end

    init init_tk(loc: Location)
    do
        _text = once "isa"
                _location = loc
    end
end

redef class TKwonce
    redef fun parser_index: Int
    do
        return 41
    end

    init init_tk(loc: Location)
    do
        _text = once "once"
                _location = loc
    end
end

redef class TKwsuper
    redef fun parser_index: Int
    do
        return 42
    end

    init init_tk(loc: Location)
    do
        _text = once "super"
                _location = loc
    end
end

redef class TKwself
    redef fun parser_index: Int
    do
        return 43
    end

    init init_tk(loc: Location)
    do
        _text = once "self"
                _location = loc
    end
end

redef class TKwtrue
    redef fun parser_index: Int
    do
        return 44
    end

    init init_tk(loc: Location)
    do
        _text = once "true"
                _location = loc
    end
end

redef class TKwfalse
    redef fun parser_index: Int
    do
        return 45
    end

    init init_tk(loc: Location)
    do
        _text = once "false"
                _location = loc
    end
end

redef class TKwnull
    redef fun parser_index: Int
    do
        return 46
    end

    init init_tk(loc: Location)
    do
        _text = once "null"
                _location = loc
    end
end

redef class TKwas
    redef fun parser_index: Int
    do
        return 47
    end

    init init_tk(loc: Location)
    do
        _text = once "as"
                _location = loc
    end
end

redef class TKwnullable
    redef fun parser_index: Int
    do
        return 48
    end

    init init_tk(loc: Location)
    do
        _text = once "nullable"
                _location = loc
    end
end

redef class TKwisset
    redef fun parser_index: Int
    do
        return 49
    end

    init init_tk(loc: Location)
    do
        _text = once "isset"
                _location = loc
    end
end

redef class TKwlabel
    redef fun parser_index: Int
    do
        return 50
    end

    init init_tk(loc: Location)
    do
        _text = once "label"
                _location = loc
    end
end

redef class TOpar
    redef fun parser_index: Int
    do
        return 51
    end

    init init_tk(loc: Location)
    do
        _text = once "("
                _location = loc
    end
end

redef class TCpar
    redef fun parser_index: Int
    do
        return 52
    end

    init init_tk(loc: Location)
    do
        _text = once ")"
                _location = loc
    end
end

redef class TObra
    redef fun parser_index: Int
    do
        return 53
    end

    init init_tk(loc: Location)
    do
        _text = once "["
                _location = loc
    end
end

redef class TCbra
    redef fun parser_index: Int
    do
        return 54
    end

    init init_tk(loc: Location)
    do
        _text = once "]"
                _location = loc
    end
end

redef class TComma
    redef fun parser_index: Int
    do
        return 55
    end

    init init_tk(loc: Location)
    do
        _text = once ","
                _location = loc
    end
end

redef class TColumn
    redef fun parser_index: Int
    do
        return 56
    end

    init init_tk(loc: Location)
    do
        _text = once ":"
                _location = loc
    end
end

redef class TQuad
    redef fun parser_index: Int
    do
        return 57
    end

    init init_tk(loc: Location)
    do
        _text = once "::"
                _location = loc
    end
end

redef class TAssign
    redef fun parser_index: Int
    do
        return 58
    end

    init init_tk(loc: Location)
    do
        _text = once "="
                _location = loc
    end
end

redef class TPluseq
    redef fun parser_index: Int
    do
        return 59
    end

    init init_tk(loc: Location)
    do
        _text = once "+="
                _location = loc
    end
end

redef class TMinuseq
    redef fun parser_index: Int
    do
        return 60
    end

    init init_tk(loc: Location)
    do
        _text = once "-="
                _location = loc
    end
end

redef class TDotdotdot
    redef fun parser_index: Int
    do
        return 61
    end

    init init_tk(loc: Location)
    do
        _text = once "..."
                _location = loc
    end
end

redef class TDotdot
    redef fun parser_index: Int
    do
        return 62
    end

    init init_tk(loc: Location)
    do
        _text = once ".."
                _location = loc
    end
end

redef class TDot
    redef fun parser_index: Int
    do
        return 63
    end

    init init_tk(loc: Location)
    do
        _text = once "."
                _location = loc
    end
end

redef class TPlus
    redef fun parser_index: Int
    do
        return 64
    end

    init init_tk(loc: Location)
    do
        _text = once "+"
                _location = loc
    end
end

redef class TMinus
    redef fun parser_index: Int
    do
        return 65
    end

    init init_tk(loc: Location)
    do
        _text = once "-"
                _location = loc
    end
end

redef class TStar
    redef fun parser_index: Int
    do
        return 66
    end

    init init_tk(loc: Location)
    do
        _text = once "*"
                _location = loc
    end
end

redef class TSlash
    redef fun parser_index: Int
    do
        return 67
    end

    init init_tk(loc: Location)
    do
        _text = once "/"
                _location = loc
    end
end

redef class TPercent
    redef fun parser_index: Int
    do
        return 68
    end

    init init_tk(loc: Location)
    do
        _text = once "%"
                _location = loc
    end
end

redef class TEq
    redef fun parser_index: Int
    do
        return 69
    end

    init init_tk(loc: Location)
    do
        _text = once "=="
                _location = loc
    end
end

redef class TNe
    redef fun parser_index: Int
    do
        return 70
    end

    init init_tk(loc: Location)
    do
        _text = once "!="
                _location = loc
    end
end

redef class TLt
    redef fun parser_index: Int
    do
        return 71
    end

    init init_tk(loc: Location)
    do
        _text = once "<"
                _location = loc
    end
end

redef class TLe
    redef fun parser_index: Int
    do
        return 72
    end

    init init_tk(loc: Location)
    do
        _text = once "<="
                _location = loc
    end
end

redef class TLl
    redef fun parser_index: Int
    do
        return 73
    end

    init init_tk(loc: Location)
    do
        _text = once "<<"
                _location = loc
    end
end

redef class TGt
    redef fun parser_index: Int
    do
        return 74
    end

    init init_tk(loc: Location)
    do
        _text = once ">"
                _location = loc
    end
end

redef class TGe
    redef fun parser_index: Int
    do
        return 75
    end

    init init_tk(loc: Location)
    do
        _text = once ">="
                _location = loc
    end
end

redef class TGg
    redef fun parser_index: Int
    do
        return 76
    end

    init init_tk(loc: Location)
    do
        _text = once ">>"
                _location = loc
    end
end

redef class TStarship
    redef fun parser_index: Int
    do
        return 77
    end

    init init_tk(loc: Location)
    do
        _text = once "<=>"
                _location = loc
    end
end

redef class TBang
    redef fun parser_index: Int
    do
        return 78
    end

    init init_tk(loc: Location)
    do
        _text = once "!"
                _location = loc
    end
end

redef class TClassid
    redef fun parser_index: Int
    do
        return 79
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TId
    redef fun parser_index: Int
    do
        return 80
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TAttrid
    redef fun parser_index: Int
    do
        return 81
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TNumber
    redef fun parser_index: Int
    do
        return 82
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TFloat
    redef fun parser_index: Int
    do
        return 83
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TChar
    redef fun parser_index: Int
    do
        return 84
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TString
    redef fun parser_index: Int
    do
        return 85
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TStartString
    redef fun parser_index: Int
    do
        return 86
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TMidString
    redef fun parser_index: Int
    do
        return 87
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end

redef class TEndString
    redef fun parser_index: Int
    do
        return 88
    end

    init init_tk(text: String, loc: Location)
    do
        _text = text
                _location = loc
    end
end


redef class EOF
    redef fun parser_index: Int
    do
        return 89
    end

    init(loc: Location)
    do
        _text = ""
                _location = loc
    end
end

redef class AError
    readable var _message: String

    init init_error(message: String, loc: Location)
    do
                init(loc)
                _message = message
    end
end


# The lexer extract NIT tokens from an input stream.
# It is better user with the Parser
class Lexer
special TablesCapable
        # Last peeked token
        var _token: nullable Token

        # Lexer current state
        var _state: Int = 0

        # Name of the stream (as given to tokens)
        readable var _filename: String

        # Input stream where character are read
        var _stream: IStream

        # Pushback buffer to store unread character
        var _stream_buf: Buffer

        # Number of character stored in the pushback buffer
        var _stream_pos: Int

        # Current line number in the input stream
        var _line: Int = 0

        # Current column in the input stream
        var _pos: Int = 0

        # Was the last character a cariage-return?
        var _cr: Bool = false

        # If the end of stream?
        var _eof: Bool = false

        # Current working text read from the input stream
        var _text: Buffer

        # Constante state values
        private fun state_initial: Int do return 0 end

        # Create a new lexer for a stream (and a name)
        init(stream: IStream, fname: String)
        do
                _filename = fname
                _text = new Buffer
                _stream = stream
                _stream_pos = -1
                _stream_buf = new Buffer
        end

        # Give the next token (but do not consume it)
        fun peek: Token
        do
                while _token == null do
                        _token = get_token
                end
                return _token.as(not null)
        end

        # Give and consume the next token
        fun next: Token
        do
                var result = _token
                while result == null do
                        result = get_token
                end
                _token = null
                return result.as(not null)
        end

        # Get a token, or null if it is discarded
        private fun get_token: nullable Token
        do
                var dfa_state = 0

                var start_pos = _pos
                var start_line = _line

                var accept_state = -1
                var accept_token = -1
                var accept_length = -1
                var accept_pos = -1
                var accept_line = -1

                var text = _text
                text.clear

                loop
                        var c = get_char

                        if c != -1 then
                                var cr = _cr
                                var line = _line
                                var pos = _pos
                                if c == 10 then
                                        if cr then
                                                cr = false
                                        else
                                                line = line + 1
                                                pos = 0
                                        end
                                else if c == 13 then
                                        line = line + 1
                                        pos = 0
                                        cr = true
                                else
                                        pos = pos + 1
                                        cr = false
                                end

                                text.add(c.ascii)

                                loop
                                        var old_state = dfa_state
                                        if dfa_state < -1 then
                                                old_state = -2 - dfa_state
                                        end

                                        dfa_state = -1

                                        var low = 0
                                        var high = lexer_goto(old_state, 0) - 1

                                        if high >= 0 then
                                                while low <= high do
                                                        var middle = (low + high) / 2
                                                        var offset = middle * 3 + 1 # +1 because length is at 0

                                                        if c < lexer_goto(old_state, offset) then
                                                                high = middle - 1
                                                        else if c > lexer_goto(old_state, offset+1) then
                                                                low = middle + 1
                                                        else
                                                                dfa_state = lexer_goto(old_state, offset+2)
                                                                break
                                                        end
                                                end
                                        end
                                        if dfa_state > -2 then break
                                end

                                _cr = cr
                                _line = line
                                _pos = pos
                        else
                                dfa_state = -1
                        end

                        if dfa_state >= 0 then
                                var tok = lexer_accept(dfa_state)
                                if tok != -1 then
                                        accept_state = dfa_state
                                        accept_token = tok
                                        accept_length = text.length
                                        accept_pos = _pos
                                        accept_line = _line
                                end
                        else
                                if accept_state != -1 then
                                        var location = new Location(_filename, start_line + 1, accept_line + 1, start_pos + 1, accept_pos)
                                        _pos = accept_pos
                                        _line = accept_line
                                        push_back(accept_length)
                                        if accept_token == 0 then
                                                return null
                                        end
                                        if accept_token == 1 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TEol.init_tk(token_text, location)
                                        end
                                        if accept_token == 2 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TComment.init_tk(token_text, location)
                                        end
                                        if accept_token == 3 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TKwmodule.init_tk(token_text, location)
                                        end
                                        if accept_token == 4 then
                                                return new TKwimport.init_tk(location)
                                        end
                                        if accept_token == 5 then
                                                return new TKwclass.init_tk(location)
                                        end
                                        if accept_token == 6 then
                                                return new TKwabstract.init_tk(location)
                                        end
                                        if accept_token == 7 then
                                                return new TKwinterface.init_tk(location)
                                        end
                                        if accept_token == 8 then
                                                return new TKwuniversal.init_tk(location)
                                        end
                                        if accept_token == 9 then
                                                return new TKwspecial.init_tk(location)
                                        end
                                        if accept_token == 10 then
                                                return new TKwend.init_tk(location)
                                        end
                                        if accept_token == 11 then
                                                return new TKwmeth.init_tk(location)
                                        end
                                        if accept_token == 12 then
                                                return new TKwtype.init_tk(location)
                                        end
                                        if accept_token == 13 then
                                                return new TKwinit.init_tk(location)
                                        end
                                        if accept_token == 14 then
                                                return new TKwredef.init_tk(location)
                                        end
                                        if accept_token == 15 then
                                                return new TKwis.init_tk(location)
                                        end
                                        if accept_token == 16 then
                                                return new TKwdo.init_tk(location)
                                        end
                                        if accept_token == 17 then
                                                return new TKwreadable.init_tk(location)
                                        end
                                        if accept_token == 18 then
                                                return new TKwwritable.init_tk(location)
                                        end
                                        if accept_token == 19 then
                                                return new TKwvar.init_tk(location)
                                        end
                                        if accept_token == 20 then
                                                return new TKwintern.init_tk(location)
                                        end
                                        if accept_token == 21 then
                                                return new TKwextern.init_tk(location)
                                        end
                                        if accept_token == 22 then
                                                return new TKwprotected.init_tk(location)
                                        end
                                        if accept_token == 23 then
                                                return new TKwprivate.init_tk(location)
                                        end
                                        if accept_token == 24 then
                                                return new TKwintrude.init_tk(location)
                                        end
                                        if accept_token == 25 then
                                                return new TKwif.init_tk(location)
                                        end
                                        if accept_token == 26 then
                                                return new TKwthen.init_tk(location)
                                        end
                                        if accept_token == 27 then
                                                return new TKwelse.init_tk(location)
                                        end
                                        if accept_token == 28 then
                                                return new TKwwhile.init_tk(location)
                                        end
                                        if accept_token == 29 then
                                                return new TKwloop.init_tk(location)
                                        end
                                        if accept_token == 30 then
                                                return new TKwfor.init_tk(location)
                                        end
                                        if accept_token == 31 then
                                                return new TKwin.init_tk(location)
                                        end
                                        if accept_token == 32 then
                                                return new TKwand.init_tk(location)
                                        end
                                        if accept_token == 33 then
                                                return new TKwor.init_tk(location)
                                        end
                                        if accept_token == 34 then
                                                return new TKwnot.init_tk(location)
                                        end
                                        if accept_token == 35 then
                                                return new TKwreturn.init_tk(location)
                                        end
                                        if accept_token == 36 then
                                                return new TKwcontinue.init_tk(location)
                                        end
                                        if accept_token == 37 then
                                                return new TKwbreak.init_tk(location)
                                        end
                                        if accept_token == 38 then
                                                return new TKwabort.init_tk(location)
                                        end
                                        if accept_token == 39 then
                                                return new TKwassert.init_tk(location)
                                        end
                                        if accept_token == 40 then
                                                return new TKwnew.init_tk(location)
                                        end
                                        if accept_token == 41 then
                                                return new TKwisa.init_tk(location)
                                        end
                                        if accept_token == 42 then
                                                return new TKwonce.init_tk(location)
                                        end
                                        if accept_token == 43 then
                                                return new TKwsuper.init_tk(location)
                                        end
                                        if accept_token == 44 then
                                                return new TKwself.init_tk(location)
                                        end
                                        if accept_token == 45 then
                                                return new TKwtrue.init_tk(location)
                                        end
                                        if accept_token == 46 then
                                                return new TKwfalse.init_tk(location)
                                        end
                                        if accept_token == 47 then
                                                return new TKwnull.init_tk(location)
                                        end
                                        if accept_token == 48 then
                                                return new TKwas.init_tk(location)
                                        end
                                        if accept_token == 49 then
                                                return new TKwnullable.init_tk(location)
                                        end
                                        if accept_token == 50 then
                                                return new TKwisset.init_tk(location)
                                        end
                                        if accept_token == 51 then
                                                return new TKwlabel.init_tk(location)
                                        end
                                        if accept_token == 52 then
                                                return new TOpar.init_tk(location)
                                        end
                                        if accept_token == 53 then
                                                return new TCpar.init_tk(location)
                                        end
                                        if accept_token == 54 then
                                                return new TObra.init_tk(location)
                                        end
                                        if accept_token == 55 then
                                                return new TCbra.init_tk(location)
                                        end
                                        if accept_token == 56 then
                                                return new TComma.init_tk(location)
                                        end
                                        if accept_token == 57 then
                                                return new TColumn.init_tk(location)
                                        end
                                        if accept_token == 58 then
                                                return new TQuad.init_tk(location)
                                        end
                                        if accept_token == 59 then
                                                return new TAssign.init_tk(location)
                                        end
                                        if accept_token == 60 then
                                                return new TPluseq.init_tk(location)
                                        end
                                        if accept_token == 61 then
                                                return new TMinuseq.init_tk(location)
                                        end
                                        if accept_token == 62 then
                                                return new TDotdotdot.init_tk(location)
                                        end
                                        if accept_token == 63 then
                                                return new TDotdot.init_tk(location)
                                        end
                                        if accept_token == 64 then
                                                return new TDot.init_tk(location)
                                        end
                                        if accept_token == 65 then
                                                return new TPlus.init_tk(location)
                                        end
                                        if accept_token == 66 then
                                                return new TMinus.init_tk(location)
                                        end
                                        if accept_token == 67 then
                                                return new TStar.init_tk(location)
                                        end
                                        if accept_token == 68 then
                                                return new TSlash.init_tk(location)
                                        end
                                        if accept_token == 69 then
                                                return new TPercent.init_tk(location)
                                        end
                                        if accept_token == 70 then
                                                return new TEq.init_tk(location)
                                        end
                                        if accept_token == 71 then
                                                return new TNe.init_tk(location)
                                        end
                                        if accept_token == 72 then
                                                return new TLt.init_tk(location)
                                        end
                                        if accept_token == 73 then
                                                return new TLe.init_tk(location)
                                        end
                                        if accept_token == 74 then
                                                return new TLl.init_tk(location)
                                        end
                                        if accept_token == 75 then
                                                return new TGt.init_tk(location)
                                        end
                                        if accept_token == 76 then
                                                return new TGe.init_tk(location)
                                        end
                                        if accept_token == 77 then
                                                return new TGg.init_tk(location)
                                        end
                                        if accept_token == 78 then
                                                return new TStarship.init_tk(location)
                                        end
                                        if accept_token == 79 then
                                                return new TBang.init_tk(location)
                                        end
                                        if accept_token == 80 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TClassid.init_tk(token_text, location)
                                        end
                                        if accept_token == 81 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TId.init_tk(token_text, location)
                                        end
                                        if accept_token == 82 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TAttrid.init_tk(token_text, location)
                                        end
                                        if accept_token == 83 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TNumber.init_tk(token_text, location)
                                        end
                                        if accept_token == 84 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TFloat.init_tk(token_text, location)
                                        end
                                        if accept_token == 85 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TChar.init_tk(token_text, location)
                                        end
                                        if accept_token == 86 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TString.init_tk(token_text, location)
                                        end
                                        if accept_token == 87 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TStartString.init_tk(token_text, location)
                                        end
                                        if accept_token == 88 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TMidString.init_tk(token_text, location)
                                        end
                                        if accept_token == 89 then
                                                var token_text = text.substring(0, accept_length)
                                                return new TEndString.init_tk(token_text, location)
                                        end
                                else
                                        var location = new Location(_filename, start_line + 1, start_line + 1, start_pos + 1, start_pos + 1)
                                        if text.length > 0 then
                                                var token = new AError.init_error("Syntax error: unknown token {text}.", location)
                                                return token
                                        else
                                                var token = new EOF(location)
                                                return token
                                        end
                                end
                        end
                end
        end

        # Read the next character.
        # The character is read from the stream of from the pushback buffer.
        private fun get_char: Int
        do
                if _eof then
                        return -1
                end

                var result: Int

                var sp = _stream_pos
                if sp >= 0 then
                        var res = _stream_buf[_stream_pos]
                        _stream_pos = sp - 1
                        result = res.ascii
                else
                        result = _stream.read_char
                end

                if result == -1 then
                        _eof = true
                end

                return result
        end

        # Unread some characters.
        # Unread characters are stored in the pushback buffer.
        private fun push_back(accept_length: Int)
        do
                var length = _text.length
                var i = length - 1
                while i >= accept_length do
                        _eof = false
                        _stream_pos = _stream_pos + 1
                        _stream_buf[_stream_pos] = _text[i]
                        i = i - 1
                end
        end
end