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   "source": [
    "# Hy Lisp\n",
    "\n",
    "Examples of Lisp, and discussion of video of final project\n",
    "\n",
    "How does Common Lisp differ from Scheme? Typically:\n",
    "\n",
    "* Lisp often has Dynamic Scope vs. Scheme always has Lexical Scope \n",
    "* Syntax differences (Lisp has defn vs. Scheme's define ... (lambda ...)) \n",
    "* Lisp is large and unwieldy\n",
    "* Scheme is and elegant\n",
    "* Lisp is practical\n",
    "* Scheme is beautiful\n",
    "* Lisp uses nil for \"empty list\"; it is also false\n",
    "* Scheme uses '() for \"empty list\"; only #f is false\n",
    "* Lisp uses different scopes for variables and functions !?\n",
    "\n",
    "How does Hy Lisp differ from Common Lisp?\n",
    "\n",
    "* Hy Lisp has Python's scoping rules, lexically scoped ... sorta\n",
    "* Hy Lisp is really just Python with different syntax\n",
    "* Hy Lisp uses Python's stack for function calls --- no trampoline, or Tail Call Elimination, etc.\n",
    "* Hy Lisp has Lisp-if and Python-if\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Videos and Blogs\n",
    "\n",
    "1. http://technicae.cogitat.io/2014/11/scientific-computing-with-hy.html - Hy computing\n",
    "1. http://nbviewer.ipython.org/github/bollwyvl/hy_kernel/blob/master/notebooks/Tutorial.ipynb - Hy notebook\n",
    "1. https://www.youtube.com/watch?v=E7hTimGmGBs - Hy video\n",
    "2. https://www.youtube.com/watch?v=P76Vbsk_3J0 - Clojure video\n",
    "3. https://www.youtube.com/watch?v=0Vq2rcjWbTc - Animvs video\n",
    "\n",
    "## Final Project + Video Rubric\n",
    "\n",
    "* Quality - 20%\n",
    "* Programming Languages integration - connection to PL ideas, such as scope, continuations, internals, closures, parser, lexer, interpreter, etc. - 20%\n",
    "* Introduction to new language - 20%\n",
    "* Code and documentation effort - 20%\n",
    "* Conversation on videos - 20%\n",
    "\n",
    "**Bonus**: up to 10%, examples:\n",
    "\n",
    "* creativity\n",
    "* effective use of media (eg, animations, varied video sequences)\n",
    "* extensive docs, code integration\n",
    "\n",
    "**Due**: Monday, Dec 15, 2014 8am\n",
    "\n",
    "Notebook on Hy Lisp:\n",
    "\n",
    "http://nbviewer.ipython.org/github/bollwyvl/hy_kernel/blob/master/notebooks/Tutorial.ipynb\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Created file '/home/dblank/.ipython/kernels/hy/kernel.json'.\n"
     ]
    }
   ],
   "source": [
    "%%file ~/.ipython/kernels/hy/kernel.json\n",
    "\n",
    "{\n",
    "  \"argv\": [\"python\", \"-m\", \"hy_kernel.hy_kernel\", \"-f\", \"{connection_file}\"],\n",
    "  \"display_name\": \"Hy Lisp\",\n",
    "  \"language\": \"hy\",\n",
    "  \"codemirror_mode\": \"hy\",\n",
    "  \"language_info\": {\n",
    "    \"name\": \"hy\",\n",
    "    \"codemirror_mode\": {\n",
    "      \"name\": \"hy\"\n",
    "    },\n",
    "    \"mimetype\": \"text/x-hylang\",\n",
    "    \"pygments_lexer\": \"ipython3\"\n",
    "  },\n",
    "  \"help_links\": [\n",
    "    {\n",
    "      \"text\": \"Hy Documentation\",\n",
    "      \"link\": \"http://docs.hylang.org/\"\n",
    "    },\n",
    "    {\n",
    "      \"text\": \"Hy Google Group\",\n",
    "      \"link\": \"https://groups.google.com/forum/#!forum/hylang-discuss\"\n",
    "    },\n",
    "    {\n",
    "      \"text\": \"Hy Github\",\n",
    "      \"link\": \"https://github.com/hylang/hy\"\n",
    "    }\n",
    "  ]\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Lisp"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "(defn simple-conversation ()\n",
    "   (print \"Hello!  I'd like to get to know you.  Tell me about yourself!\")\n",
    "   (setv name (raw_input \"What is your name? \"))\n",
    "   (setv age (raw_input \"What is your age? \"))\n",
    "   (print (+ \"Hello \" name \"!  I see you are \"\n",
    "             age \" years old.\"))\n",
    "   None)\n",
    "\n",
    "(simple-conversation)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "(defn fact (n)\n",
    "    (if (= n 1)\n",
    "        1\n",
    "        (* n (fact (- n 1)))))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "120L"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(fact 5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "6L"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "((let [[x 5]] \n",
    "   (lambda () (+ x 1))))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "67526802209645841583879061361800814224269427869589384312198268703685091643180416969132446952698303794226010370578672908593198347699886928591906501031587651846976759681112609524787093848004428636186893395272784450630354080243217646658024696659065951793757223520229235577548653833681102170973893746054649126415909143150172860721156685810655759230011450132992176454983227538696340112610447029002337004887877266387704586077293585433151612518800147764461182680822867092786694982831838641800997499819339206579415325649748486265233918911087114592440896594062675914294925816719862178374679272092637524786939036290035924271782253738059886933923447877769583003016705363339031413069155837518524761078342052635475632113169618774549275701480106933362990003732589370593557325299434734459295866728988740794174654391479926000848846686708729736713207285203712732201272410830836913052635365082888725171636081587151603468291106754640398232146673627370895934090777828827549554232436190464827998683927179246029919443251026464452337939599198528297828591122689960620361238248313158071643395848405047261412680039877733761849874447323867911712630023171745968278465780558568067035013885275080292137360491875164947724464221693533755035300065350065137490832039523382963747026185653050331832380991844842560750923543775188582096487476950254418365198999674684417286265442786651594404781622946901879166382930714196908227460133027605817864877377712193142137625430353718448269390732615776645283198828602917680224041088993892610506802195917247838900106910698057030379190571057605849323113308634452008179881165616449767648354161225066967961297609698742737923389391615207441152319392845687673311899247085327703421862972871644495409572259985563215471482083325653231777113271326579970310755604973969708949477374254974480294652427022436705380184064008853457214518515270985563195412993145274057688634448812449445800617631162768243125606424844709372022149908463572254912654907763445758543980999149122998104378965626781898655221443263601405152073199706585080288735040205417371277253096243200000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000\n"
     ]
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   ],
   "source": [
    "(defn display (v) (print v) 'ok)\n",
    "(try\n",
    "    (display (fact 900))\n",
    "    (catch [e Exception] 'ok)\n",
    ";;    (else (print \"no errors\"))\n",
    "    (finally 'ok)\n",
    "  )"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "(defn display (v) (print v) 'ok)\n",
    "(try\n",
    "    (display (fact 1000))\n",
    "    (catch [e Exception] 'ok)\n",
    ";;    (else (print \"no errors\"))\n",
    "    (finally 'ok)\n",
    "  )"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Cool Macro tricks\n",
    "\n",
    "### \"Threading Macro\" from Clojure"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "`sh` is a Python library that wraps up shell commands as Python functions.\n",
    "\n",
    "* cat - concatenate \n",
    "* grep - search\n",
    "* wc - word/character/line count\n",
    "\n",
    "In Python, you would write:\n",
    "\n",
    "```python\n",
    "from sh import cat, grep, wc\n",
    "\n",
    "wc(grep(cat(\"/usr/share/dict/words\"), \"-E\", \"^hy\"), \"-l\")\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### In Hy Lisp:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "(import [sh [cat grep wc]])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "210"
      ]
     },
     "execution_count": 31,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(wc (grep (cat \"/usr/share/dict/words\") \"-E\" \"^hy\") \"-l\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "210"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(-> (cat \"/usr/share/dict/words\") (grep \"-E\" \"^hy\") (wc \"-l\"))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## How is Hy implemented?\n",
    "\n",
    "From hy_kernel.py:"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "```python\n",
    "class HyKernel(IPythonKernel):\n",
    "   def do_execute(self, code, *args, **kwargs):\n",
    "        '''                                                                     \n",
    "        Generate python code, and have IPythonKernel run it, or show why we     \n",
    "        couldn't have python code.                                              \n",
    "        '''\n",
    "        try:\n",
    "            tokens = tokenize(code)\n",
    "            _ast = hy_compile(tokens, '__console__', root=ast.Interactive)\n",
    "            _ast_for_print = ast.Module()\n",
    "            _ast_for_print.body = _ast.body\n",
    "            code = astor.codegen.to_source(_ast_for_print)\n",
    "        except Exception as err:\n",
    "            if (not hasattr(err, 'source')) or not err.source:\n",
    "                err.source = code\n",
    "            # shell will find the last exception                                \n",
    "            self.shell.showsyntaxerror()\n",
    "            # an empty code cell is basically a no-op                           \n",
    "            code = ''\n",
    "        return super(HyKernel, self).do_execute(code, *args, **kwargs)\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Macros\n",
    "\n",
    "### Hy Philosophy:\n",
    "\n",
    "```\n",
    "(defmacro -> [head &rest rest]\n",
    "  (setv ret head)\n",
    "  (for* [node rest]\n",
    "    (if (not (isinstance node HyExpression))\n",
    "      (setv node `(~node)))\n",
    "    (.insert node 1 ret)\n",
    "    (setv ret node))\n",
    "  ret)\n",
    "  ```\n",
    "  \n",
    "  ### Scheme Philosophy\n",
    "  \n",
    "  ```\n",
    "  (define-syntax ->\n",
    "   [(-> ?a) ?a]     \n",
    "   [(-> ?a (?b . ?args) . ?rest)\n",
    "    (-> (?b ?a . ?args) . ?rest)])\n",
    " ```"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'HELLO!'"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "(-> '\"hello\"  (+ \"!\") .upper str)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
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  "kernelspec": {
   "display_name": "Calysto Scheme 2",
   "language": "scheme",
   "name": "calysto_scheme"
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   "codemirror_mode": {
    "name": "scheme"
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   "mimetype": "text/x-scheme",
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