ruamel multiline scalar roundtripping

ruamel.yaml example roundtrips.ipynb

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     "text": [
      "Defaulting to user installation because normal site-packages is not writeable\n",
      "Requirement already satisfied: ruamel.yaml in /usr/lib/python3.11/site-packages (0.17.24)\n",
      "Requirement already satisfied: ruamel.yaml.clib>=0.2.7 in /usr/lib64/python3.11/site-packages (from ruamel.yaml) (0.2.7)\n"
     ]
    }
   ],
   "source": [
    "import sys\n",
    "!{sys.executable} -m pip install ruamel.yaml"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 97,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "# demonstrates roudntripping of scalar formatting and comments + whitespace\n",
      "\n",
      "default: i am string\n",
      "single: 'single'\n",
      "double: \"\" # and empty as well\n",
      "\n",
      "\n",
      "# final line break and any trailing empty lines are clipped\n",
      "clipped: |\n",
      "  clipped example\n",
      "# final line break and any trailing empty lines are stripped\n",
      "stripped: |-\n",
      "  stripped example\n",
      "\n",
      "\n",
      "  below two spaces\n",
      "  key: in the string\n",
      "\n",
      "\n",
      "\n",
      "key: test\n",
      "# an awful lot of whitespace before the key above\n",
      "kept: |+\n",
      "  will keep all the trailing lines\n",
      "\n",
      "\n",
      "...\n"
     ]
    }
   ],
   "source": [
    "from ruamel.yaml import YAML\n",
    "from ruamel.yaml.scalarstring import LiteralScalarString\n",
    "\n",
    "demo = \"\"\"\\\n",
    "# demonstrates roudntripping of scalar formatting and comments + whitespace\n",
    "\n",
    "default: i am string\n",
    "single: 'single'\n",
    "double: \"\" # and empty as well\n",
    "\n",
    "\n",
    "# final line break and any trailing empty lines are clipped\n",
    "clipped: |\n",
    "  clipped example\n",
    "# final line break and any trailing empty lines are stripped\n",
    "stripped: |-\n",
    "  stripped example\n",
    "\n",
    "\n",
    "  below two spaces\n",
    "  key: in the string\n",
    "\n",
    "\n",
    "\n",
    "key: test\n",
    "# an awful lot of whitespace before the key above\n",
    "kept: |+\n",
    "  will keep all the trailing lines\n",
    "  \n",
    "  \n",
    "  \"\"\"\n",
    "\n",
    "yaml = YAML()\n",
    "yaml.preserve_quotes = True\n",
    "\n",
    "code = yaml.load(demo)\n",
    "# dump to demonstrate that everything is preserved when we no-op\n",
    "yaml.dump(code, sys.stdout)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 98,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "code['clipped']='clipped example\\n'\n",
      "# demonstrates roudntripping of scalar formatting and comments + whitespace\n",
      "\n",
      "default: i am string\n",
      "single: 'single'\n",
      "double: \"\" # and empty as well\n",
      "\n",
      "\n",
      "# final line break and any trailing empty lines are clipped\n",
      "clipped: |\n",
      "  clipped example\n",
      "# final line break and any trailing empty lines are stripped\n",
      "stripped: |-\n",
      "  stripped example\n",
      "\n",
      "\n",
      "  below two spaces\n",
      "  key: in the string\n",
      "\n",
      "\n",
      "\n",
      "key: test\n",
      "# an awful lot of whitespace before the key above\n",
      "kept: |+\n",
      "  will keep all the trailing lines\n",
      "\n",
      "\n",
      "...\n"
     ]
    }
   ],
   "source": [
    "# update clipped example\n",
    "print(f\"{code['clipped']=}\")\n",
    "code['clipped'] = \"\"\"clipped example\n",
    "\"\"\"\n",
    "yaml.dump(code, sys.stdout)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 99,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "code['stripped']='stripped example\\n\\n\\nbelow two spaces\\nkey: in the string'\n",
      "# demonstrates roudntripping of scalar formatting and comments + whitespace\n",
      "\n",
      "default: i am string\n",
      "single: 'single'\n",
      "double: \"\" # and empty as well\n",
      "\n",
      "\n",
      "# final line break and any trailing empty lines are clipped\n",
      "clipped: |\n",
      "  clipped example\n",
      "# final line break and any trailing empty lines are stripped\n",
      "stripped: |-\n",
      "  stripped example\n",
      "\n",
      "\n",
      "  below two spaces\n",
      "  key: in the string\n",
      "\n",
      "\n",
      "\n",
      "key: test\n",
      "# an awful lot of whitespace before the key above\n",
      "kept: |+\n",
      "  will keep all the trailing lines\n",
      "\n",
      "\n",
      "...\n"
     ]
    }
   ],
   "source": [
    "print(f\"{code['stripped']=}\")\n",
    "code['stripped'] = LiteralScalarString(\"\"\"stripped example\n",
    "\n",
    "\n",
    "below two spaces\n",
    "key: in the string\"\"\")\n",
    "\n",
    "yaml.dump(code, sys.stdout)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 100,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "code['kept']='will keep all the trailing lines\\n\\n\\n'\n",
      "# demonstrates roudntripping of scalar formatting and comments + whitespace\n",
      "\n",
      "default: i am string\n",
      "single: 'single'\n",
      "double: \"\" # and empty as well\n",
      "\n",
      "\n",
      "# final line break and any trailing empty lines are clipped\n",
      "clipped: |\n",
      "  clipped example\n",
      "# final line break and any trailing empty lines are stripped\n",
      "stripped: |-\n",
      "  stripped example\n",
      "\n",
      "\n",
      "  below two spaces\n",
      "  key: in the string\n",
      "\n",
      "\n",
      "\n",
      "key: test\n",
      "# an awful lot of whitespace before the key above\n",
      "kept: |+\n",
      "  will keep all the trailing lines\n",
      "\n",
      "\n",
      "...\n"
     ]
    }
   ],
   "source": [
    "print(f\"{code['kept']=}\")\n",
    "code['kept'] = LiteralScalarString(\"\"\"will keep all the trailing lines\n",
    "\n",
    "\n",
    "\"\"\")\n",
    "yaml.dump(code, sys.stdout)"
   ]
  }
 ],
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