Complicated AST manipulation looks ugly in C++. How to refactor it?

[FlatAssembler]

Here is a code I have recently written in the compiler for my programming language, written in C++:

Code:

  } else if (text.size() == 2 and
             text[1] ==
                 '=') // The assignment operators "+=", "-=", "*=" and "/="...
  {
    if (children.at(0).text.back() ==
        '[') { // https://github.com/FlatAssembler/AECforWebAssembly/issues/15
               // https://discord.com/channels/530598289813536771/847014270922391563/934823770307301416
      TreeNode fakeInnerFunctionNode("Does", lineNumber, columnNumber);
      std::string subscriptName = "tmp" + std::to_string(rand());
      TreeNode declarationOfSubscript("Integer32", lineNumber, columnNumber);
      declarationOfSubscript.children.push_back(
          TreeNode(subscriptName, lineNumber, columnNumber));
      fakeInnerFunctionNode.children.push_back(declarationOfSubscript);
      TreeNode subscriptAssignment(":=", lineNumber, columnNumber);
      subscriptAssignment.children.push_back(
          TreeNode(subscriptName, lineNumber, columnNumber));
      subscriptAssignment.children.push_back(children[0].children.at(0));
      fakeInnerFunctionNode.children.push_back(subscriptAssignment);
      TreeNode convertedToSimpleAssignment(":=", lineNumber, columnNumber);
      convertedToSimpleAssignment.children.push_back(TreeNode(
          children[0].text, children[0].lineNumber, children[0].columnNumber));
      convertedToSimpleAssignment.children[0].children.push_back(
          TreeNode(subscriptName, lineNumber, columnNumber));
      convertedToSimpleAssignment.children.push_back(
          TreeNode(text.substr(0, 1), lineNumber, columnNumber));
      convertedToSimpleAssignment.children[1].children.push_back(TreeNode(
          children[0].text, children[0].lineNumber, children[0].columnNumber));
      convertedToSimpleAssignment.children[1].children[0].children.push_back(
          TreeNode(subscriptName, lineNumber, columnNumber));
      convertedToSimpleAssignment.children[1].children.push_back(
          children.at(1));
      fakeInnerFunctionNode.children.push_back(convertedToSimpleAssignment);
      CompilationContext fakeContext = context;
      fakeContext.stackSizeOfThisScope = 0;
      fakeContext.stackSizeOfThisFunction = 0;
      assembly += fakeInnerFunctionNode.compile(fakeContext) + "\n";
    } else {
      TreeNode convertedToSimpleAssignment(":=", lineNumber, columnNumber);
      convertedToSimpleAssignment.children.push_back(children[0]);
      convertedToSimpleAssignment.children.push_back(*this);
      convertedToSimpleAssignment.children[1].text =
          convertedToSimpleAssignment.children[1].text.substr(0, 1);
      assembly += convertedToSimpleAssignment.compile(context);
    }

It definitely looks incomprehensible. How would you write it better?

I'd add dragons.

Possibly a couple of elves and a magical sword.

I have no idea what that means.

---

Have you tried turning it off then on again?

How is that supposed to help? The file in which the code is stored will (hopefully) remain unchanged.