gistfile1.clj

(defn Buffer [string]
  (set! this.string string)
  (set! this.pos 0)
  undefined)

(defn Buffer.prototype.read1 []
  (cond
    (= this.pos this.string.length)
      (do
        (set! this.pos (+ this.pos 1))
        " ")

    (> this.pos this.string.length)
      (throw "EOF while reading")

    :else
      (let [ch (this.string[this.pos])]
        (set! this.pos (+ this.pos 1))
        ch)))

(defn Buffer.prototype.lookahead [n]
  (this.string.substring this.pos (+ this.pos n)))

(defn Buffer.prototype.unread [s]
  (set! this.pos (- this.pos s.length)))

; JS Output

$env.Buffer = function (string) {
    this.string = string;
    this.pos = 0;
    return undefined;
};
$env.Buffer.prototype.read1 = function () {
    return function () {
        if (this.pos === this.string.length)
            return function () {
                this.pos = this.pos + 1;
                return ' ';
            }.call(this);
        else if (this.pos > this.string.length)
            return function () {
                throw 'EOF while reading';
            }.call(this);
        else
            return function () {
                var ch = this.string[this.pos]();
                this.pos = this.pos + 1;
                return ch;
            }.call(this);
    }.call(this);
};
$env.Buffer.prototype.lookahead = function (n) {
    return this.string.substring(this.pos, this.pos + n);
};
$env.Buffer.prototype.unread = function (s) {
    return this.pos = this.pos - s.length;
};

gistfile2.coffee

class Buffer
  constructor: (@string) ->
    @pos = 0

  read1: ->
    if @pos == @string.length
      ++@pos
      return " "
    else if @pos > @string.length
      throw 'EOF while reading'

    ch = @string[@pos]
    ++@pos
    ch

  lookahead: (n) ->
    @string.substring(@pos, @pos + n)

  unread: (str) ->
    @pos -= str.length
    

# JS Output

var Buffer;

Buffer = (function() {
  function Buffer(string) {
    this.string = string;
    this.pos = 0;
  }

  Buffer.prototype.read1 = function() {
    var ch;

    if (this.pos === this.string.length) {
      ++this.pos;
      return " ";
    } else if (this.pos > this.string.length) {
      throw 'EOF while reading';
    }
    ch = this.string[this.pos];
    ++this.pos;
    return ch;
  };

  Buffer.prototype.lookahead = function(n) {
    return this.string.substring(this.pos, this.pos + n);
  };

  Buffer.prototype.unread = function(str) {
    return this.pos -= str.length;
  };

  return Buffer;

})();