Masud_Sir/recursive_descent_parsing.ipynb

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    "print(\"Recursive Desent Parsing For following grammar\\n\")\n",
    "print(\"E->TE'\\nE'->+TE'/@\\nT->FT'\\nT'->*FT'/@\\nF->(E)/i\\n\")\n",
    "print(\"Enter the string want to be checked\\n\")\n",
    "global s\n",
    "s=(input())\n",
    "global i\n",
    "i=0\n",
    "def match(a):\n",
    "    global s\n",
    "    global i\n",
    "    if(i>=len(s)):\n",
    "        return False\n",
    "    elif(s[i]==a):\n",
    "        i+=1\n",
    "        return True\n",
    "    else:\n",
    "        return False\n",
    "def F():\n",
    "    if(match(\"(\")):\n",
    "        if(E()):\n",
    "            if(match(\")\")):\n",
    "                return True\n",
    "            else:\n",
    "                return False\n",
    "        else:\n",
    "            return False\n",
    "    elif(match(\"i\")):\n",
    "        return True\n",
    "    else:\n",
    "        return False\n",
    "def Tx():\n",
    "    if(match(\"*\")):\n",
    "        if(F()):\n",
    "            if(Tx()):\n",
    "                return True\n",
    "            else:\n",
    "                return False\n",
    "        else:\n",
    "            return False\n",
    "    else:\n",
    "        return True\n",
    "def T():\n",
    "    if(F()):\n",
    "        if(Tx()):\n",
    "            return True\n",
    "        else:\n",
    "            return False\n",
    "    else:\n",
    "        return False\n",
    "def Ex():\n",
    "    if(match(\"+\")):\n",
    "        if(T()):\n",
    "            if(Ex()):\n",
    "                return True\n",
    "            else:\n",
    "                return False\n",
    "        else:\n",
    "            return False\n",
    "    else:\n",
    "        return True\n",
    "def E():\n",
    "    if(T()):\n",
    "        if(Ex()):\n",
    "            return True\n",
    "        else:\n",
    "            return False\n",
    "    else:\n",
    "        return False\n",
    "if(E()):\n",
    "    if(i==len(s)):\n",
    "        print(\"String is accepted\")\n",
    "    else:\n",
    "         print(\"String is not accepted , Error at position\",i)\n",
    "    \n",
    "else:\n",
    "    print(\"string is not accepted ^^ \")\n",
    "\n",
    "\n",
    "# input this string : (i+i)*i it is accepted"
   ]
  }
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