function forEach(array, action) {
  for (var i = 0; i < array.length; i++)
    action(array[i]);
}

function negate(func) {
  return function() {
    return !func.apply(null, arguments);
  };
}

function reduce(combine, base, array) {
  forEach(array, function (element) {
    base = combine(base, element);
  });
  return base;
}

function count(test, array) {
  return reduce(function(total, element) {
    return total + (test(element) ? 1 : 0);
  }, 0, array);
}

function splitParagraph(text) {
  function indexOrEnd(character) {
    var index = text.indexOf(character);
    return index == -1 ? text.length : index;
  }

  function takeNormal() {
    var end = reduce(Math.min, text.length,
                     map(indexOrEnd, ["*", "{"]));
    var part = text.slice(0, end);
    text = text.slice(end);
    return part;
  }

  function takeUpTo(character) {
    var end = text.indexOf(character, 1);
    if (end == -1)
      throw new Error("Missing closing '" + character + "'");
    var part = text.slice(1, end);
    text = text.slice(end + 1);
    return part;
  }

  var fragments = [];

  while (text != "") {
    if (text.charAt(0) == "*")
      fragments.push({type: "emphasised",
                      content: takeUpTo("*")});
    else if (text.charAt(0) == "{")
      fragments.push({type: "footnote",
                      content: takeUpTo("}")});
    else
      fragments.push({type: "normal",
                      content: takeNormal()});
  }
  return fragments;
}

function processParagraph(paragraph) {
  var header = 0;
  while (paragraph.charAt(0) == "%") {
    paragraph = paragraph.slice(1);
    header++;
  }

  return {type: (header == 0 ? "p" : "h" + header),
          content: splitParagraph(paragraph)};
}

function extractFootnotes(paragraphs) {
  var footnotes = [];
  var currentNote = 0;

  function replaceFootnote(fragment) {
    if (fragment.type == "footnote") {
      currentNote++;
      footnotes.push(fragment);
      fragment.number = currentNote;
      return {type: "reference", number: currentNote};
    }
    else {
      return fragment;
    }
  }

  forEach(paragraphs, function(paragraph) {
    paragraph.content = map(replaceFootnote,
                            paragraph.content);
  });

  return footnotes;
}

function link(target, text) {
  return tag("a", [text], {href: target});
}

function htmlDoc(title, bodyContent) {
  return tag("html", [tag("head", [tag("title", [title])]),
                      tag("body", bodyContent)]);
}

function escapeHTML(text) {
  var replacements = [[/&/g, "&"], [/"/g, """],
                      [/</g, "<"], [/>/g, ">"]];
  forEach(replacements, function(replace) {
    text = text.replace(replace[0], replace[1]);
  });
  return text;
}

function renderHTML(element) {
  var pieces = [];

  function renderAttributes(attributes) {
    var result = [];
    if (attributes) {
      for (var name in attributes)
        result.push(" " + name + "="" +
                    escapeHTML(attributes[name]) + """);
    }
    return result.join("");
  }

  function render(element) {
    // Text node
    if (typeof element == "string") {
      pieces.push(escapeHTML(element));
    }
    // Empty tag
    else if (!element.content || element.content.length == 0) {
      pieces.push("<" + element.name +
                  renderAttributes(element.attributes) + "/>");
    }
    // Tag with content
    else {
      pieces.push("<" + element.name +
                  renderAttributes(element.attributes) + ">");
      forEach(element.content, render);
      pieces.push("</" + element.name + ">");
    }
  }

  render(element);
  return pieces.join("");
}

function footnote(number) {
  return tag("sup", [link("#footnote" + number,
                          String(number))]);
}

function renderFragment(fragment) {
  if (fragment.type == "reference")
    return footnote(fragment.number);
  else if (fragment.type == "emphasised")
    return tag("em", [fragment.content]);
  else if (fragment.type == "normal")
    return fragment.content;
}

function renderFootnote(footnote) {
  var anchor = tag("a", [], {name: "footnote" + footnote.number});
  var number = "[" + footnote.number + "] ";
  return tag("p", [tag("small", [anchor, number,
                                 footnote.content])]);
}

function tag(name, content, attributes) {
  return {name: name, attributes: attributes, content: content};
}

function renderParagraph(paragraph) {
  return tag(paragraph.type, map(renderFragment, paragraph.content));
}

function map(func, array) {
  var result = [];
  forEach(array, function (element) {
    result.push(func(element));
  });
  return result;
}

function renderFile(file, title) {
  var paragraphs = map(processParagraph, file.split("nn"));
  var footnotes = map(renderFootnote, extractFootnotes(paragraphs));
  var body = map(renderParagraph, paragraphs).concat(footnotes);
  return renderHTML(htmlDoc(title, body));
}

viewHTML(renderFile(recluseFile(), "The Book of Programming"));