You'll probably find this tutorial on building a text editor in Rust very useful for the actual text editor side of things.

Does someone know of a library that will allow me to print text to the terminal and then allow the user to type *over* that text?

For this and your colours question, you're going to want to be using libraries like:

• crossterm

• termion

• tui

You'll basically render the text to the terminal, maybe in a particular colour like a grey or something, and then have event handling set up which checks the user input against the current character, and changes how that character is rendered to the screen, depending on if the user input was correct or not. This can be done with the above libraries.

You cannot cleanly — the build script is used to build the library, so by definition must run before the library is built.

Clean solution

Put the type into another library and import the new library into both the build script and your original library

.
├── the_library
│   ├── Cargo.toml
│   ├── build.rs
│   └── src
│       └── lib.rs
└── the_type
    ├── Cargo.toml
    └── src
        └── lib.rs

the_type/src/lib.rs

pub struct TheCoolType;

the_library/Cargo.toml

# ...

[dependencies]
the_type = { path = "../the_type" }

[build-dependencies]
the_type = { path = "../the_type" }

the_library/build.rs

fn main() {
    the_type::TheCoolType;
}

the_library/src/lib.rs

pub fn thing() {
    the_type::TheCoolType;
}

Hacky solution

Use something like #[path] mod ... or include! to include the code twice. This is basically pure textual substitution, so it's very brittle.

.
├── Cargo.toml
├── build.rs
└── src
    ├── foo.rs
    └── lib.rs

build.rs

// One **exactly one** of this...
#[path = "src/foo.rs"]
mod foo;

// ... or this
// mod foo {
//     include!("src/foo.rs");
// }

fn main() {
    foo::TheCoolType;
}

src/lib.rs

mod foo;

pub fn thing() {
    foo::TheCoolType;
}

src/foo.rs

pub struct TheCoolType;

Having a version 1.0 isn't a requirement for crates to be usable. For instance, tokio and rocket have a combined 16M downloads, but both are pre-1.0.

That being said, serde, the premier deserialization library, is on version 1.0.118. You should see if that fits your needs.