# RefactoryString
A library to modify a string using original indices, inspired by Rich
Harris' MagicString (see [here](https://github.com/Rich-Harris/magic-string)).
[
](https://crates.io/crates/refactory_string)
[](https://github.com/hansl/refactory/actions?query=workflow%3Atest)
[](https://docs.rs/refactory_string)
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----
Suppose you have some source code and you want to modify it. If the source code that
you're using doesn't have a lossless AST parser _and_ writer, you won't be able to
parse it, update it, then save it back. This is where RefactoryString comes in
handy; it allows you to modify a text content using its original indices. It is
also very fast.
For example, you may want to replace the variable name `i` with `new_var_name` in the following code:
```
let i = 1;
println!("{}", i + 5);
```
One struggle is to do the transformation in the appropriate order (so you have
to queue all changes), and you need to reparse the AST everytime you add something
new. With `RefactoryString` you don't need to worry about it; just `overwrite`,
append or prepend to the left or right of indices in the original string, and
serialize to string;
```rust
fn do_it() -> Result<(), refactory_string::Error> {
let example = String::from(r#"let i = 1;\nprintln!("{}", i + 5);"#);
let mut rs = RefactoryString::new(&example);
rs.overwrite(4, 5, "new_var_name")?;
rs.overwrite(27, 28, "new_var_name")?; // Using indices in the original content.
assert_eq!(&rs.to_string()?, r#"let new_var_name = 1;\nprintln!("{}", new_var_name + 5);"#);
Ok(())
}
```
## Documentation
Documentation can be found [here](https://docs.rs/refactory_string) and is always
improving.
## TODO
See our issue list [here](https://github.com/hansl/refactory/labels/pkg%3Arefactory_string).