It sounds like you are trying to deserialize something that looks almost like JSON or Rust's Debug output. Normally, I would recommend looking into serde, but there isn't anything that would be able to deserialize your data out of the box.
Can you tell us more about what you are trying to achieve? There may be an easier way to do things if we tweak the problem a little bit.
I am trying to build a local website, which can accept some input text, which is not pure Rust but more less verbose. And then I convert the input text to a String of pure Rust kind, and the String will be passed to irust_repl (which is a Rust crate of evaluating String) and run the converted code.
I input the following text in the website:
It sounds like you are effectively trying to build your own programming language, and not just trying to deserialize some data.
If that's the case, I would highly suggest following the formal route of creating a lexer and parser for your programming language that parses source code into some abstract tree which represents the user's program, and from there you can traverse the tree and turn it into Rust source code (or maybe you don't need to generate & compile Rust source code at all and can just turn the tree into data that can be consumed by a program).
It's much more verbose than a simple #[derive(Deserialize)], but the code is going to be a lot more reliable and well structured than trying to bodge something together.