ref: master
./tokeniser.go
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package dirty import ( "bufio" "fmt" "io" ) // todo use reader.Peek() var skipped rune = 0 type tokenType int const ( UNKNOWN tokenType = iota LBRACKET RBRACKET STRING STRING_RAW NUMBER FLOAT CONST COMMENT EOF ) type token struct { ttype tokenType t string i *int64 f *float64 } func nextToken(reader *bufio.Reader) (token, error) { t, finished, e := nextToken_initial(reader) if finished || e != nil { return t, e } t, e = nextToken_rest(reader, t) return t, e } func nextToken_initial(reader *bufio.Reader) (token, bool, error) { var ( r rune = 0 err error = nil t token ) initialTokenLoop: for { if skipped != 0 { r = skipped skipped = 0 } else { r, _, err = reader.ReadRune() } //debugf("%c\n", r) if err != nil { if err == io.EOF { t := token{ttype: EOF} return t, true, nil } return token{}, true, fmt.Errorf("while reading: %w", err) } switch { case r == '(': return token{ttype: LBRACKET}, true, nil case r == ')': return token{ttype: RBRACKET}, true, nil case r == '#': t = token{ttype: COMMENT} break initialTokenLoop case r == '`': t = token{ttype: STRING_RAW} break initialTokenLoop case r == '\'': t = token{ttype: STRING} break initialTokenLoop case r == 't': t = token{ttype: CONST, t: "t"} break initialTokenLoop case r == 'f': t = token{ttype: CONST, t: "f"} break initialTokenLoop case r == 'n': t = token{ttype: CONST, t: "n"} break initialTokenLoop case in(r, []rune{'1', '2', '3', '4', '5', '6', '7', '8', '9', '↊', '↋', '-', '.', '·', ','}): t = token{ttype: NUMBER, t: string(r)} break initialTokenLoop case r == '0': r, _, err = reader.ReadRune() //debugf("%c\n", r) if err != nil { if err == io.EOF { t := token{ttype: EOF} return t, true, nil } return token{}, true, fmt.Errorf("while reading: %w", err) } switch r { case 'b': t = token{ttype: NUMBER, t: "0b"} break initialTokenLoop case 'o': t = token{ttype: NUMBER, t: "0o"} break initialTokenLoop case 'x': t = token{ttype: NUMBER, t: "0x"} break initialTokenLoop default: skipped = r var zero int64 = 0 return token{ttype: NUMBER, i: &zero}, true, nil } case in(r, []rune{' ', '\t', '\n', '\r'}): continue default: return token{}, true, nil } } return t, false, err } func nextToken_rest(reader *bufio.Reader, t token) (token, error) { var ( r rune err error = nil escaping bool = false stringRawIndent string = "" stringRawIndentSkip string = "" stringRawState int = 0 // todo enum ) tokenLoop: for { if skipped != 0 { r = skipped skipped = 0 } else { r, _, err = reader.ReadRune() } //debugf("%c\n", r) // todo line, column if err != nil { if err == io.EOF { if t.ttype == STRING || t.ttype == STRING_RAW { return token{}, NewUnterminatedError("string", t.t) } else { return token{ttype: EOF}, nil } } return token{}, fmt.Errorf("while reading: %w", err) } switch t.ttype { case COMMENT: if r != '\n' { t.t += string(r) } else { break tokenLoop } case STRING: if !escaping && r == '\'' { t, err = parseString(t) if err != nil { return token{}, err } break tokenLoop } else if r == '\n' { return token{}, NewUnterminatedError("string", t.t) } else { t.t += string(r) } if escaping { escaping = false } else if r == '\\' { escaping = true } case STRING_RAW: if stringRawState == 0 { if r != '\n' { return token{}, NewRawStringError("missing new line after opening `") } else { stringRawState = 1 continue } } if stringRawState == 1 { if r == ' ' || r == '\t' { stringRawIndent += string(r) } else { stringRawState = 2 t.t += string(r) } continue } if stringRawState == 2 { // fixme assumes lines ending with \n; get to end of line if r == '\n' { stringRawState = 3 stringRawIndentSkip = "" } t.t += string(r) continue } if stringRawState == 3 { if len(stringRawIndentSkip) == 0 && r == '`' { break tokenLoop } if len(stringRawIndentSkip) < len(stringRawIndent) { stringRawIndentSkip += string(r) } else { if stringRawIndent != stringRawIndentSkip { // todo convert whitespace to escape codes return token{}, NewRawStringError("Indent ‘" + stringRawIndent + "’ does not begin with ‘" + stringRawIndentSkip + "’") } skipped = r stringRawState = 2 } } case CONST: if t.t[0] == 't' && in(r, []rune{'r', 'u', 'e'}) && len(t.t) < 4 { t.t += string(r) continue } if t.t[0] == 'f' && in(r, []rune{'a', 'l', 's', 'e'}) && len(t.t) < 5 { t.t += string(r) continue } if in(r, []rune{'u', 'l'}) && len(t.t) < 4 { t.t += string(r) continue } skipped = r t, err = parseConst(t) break tokenLoop case NUMBER: if t.t[0] == '0' && t.t[1] == 'b' && in(r, []rune{'0', '1', ','}) { t.t += string(r) continue } if t.t[0] == '0' && t.t[1] == 'o' && in(r, []rune{'0', '1', '2', '3', '4', '5', '6', '7'}) { t.t += string(r) continue } if t.t[0] == '0' && t.t[1] == 'x' && in(r, []rune{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'A', 'B', 'C', 'D', 'E', 'F'}) { t.t += string(r) continue } if in(r, []rune{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '↊', '↋', ',', '.', '·', 'e', '-'}) { t.t += string(r) continue } skipped = r t, err = parseNumber(t) // todo errors that are not CommaError <- NumberError break tokenLoop } } return t, err } func in(c rune, expected []rune) bool { for _, e := range expected { if c == e { return true } } return false } |