examples/01 A very simple Counter contract.ipynb

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   "source": [
    "# A very simple Counter contract\n",
    "\n",
    "Let's start writing a contract in python that stores a number which everyone can increment:"
   ]
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   "cell_type": "code",
   "execution_count": 1,
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   "source": [
    "def counter_contract():\n",
    "    # introduce a state called count which holds a single value\n",
    "    count = Variable()\n",
    "    \n",
    "    # @construct means that this is the function that will be called when the smart contract is created\n",
    "    @construct\n",
    "    def constructor():\n",
    "        count.set(0)\n",
    "        \n",
    "    # @export makes this function public, so it can be called by anyone on a deployed contract    \n",
    "    @export\n",
    "    def increment():\n",
    "        count.set(count.get() + 1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "To interact with smart contracts we need a client:"
   ]
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   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "from contracting.client import ContractingClient\n",
    "client = ContractingClient(signer='ren')"
   ]
  },
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Next we will submit the contract to the client:"
   ]
  },
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   "source": [
    "client.submit(counter_contract)"
   ]
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now we can get the submitted contract to interact with it:"
   ]
  },
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   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "contract = client.get_contract('counter_contract')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Let's investigate the counter:"
   ]
  },
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    "contract.count.get()"
   ]
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   "cell_type": "markdown",
   "metadata": {},
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    "It is 0 as expected because we initialized it to 0 in the constructor function.\n",
    "\n",
    "Everyone can increment the counter by calling the public increment function:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "contract.increment()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Let's investigate the counter again:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "contract.count.get()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Seems like our increment function works.\n",
    "\n",
    "This concludes our first look into writing smart contracts in Python on Lamden. Dive deeper by looking at the next example. "
   ]
  }
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