rescue-blanket -- escape values while they are being formatted

This crate provides Escaped, a wrapper for escaping special characters and constructs in values while formatting them, and Escaper, a trait for defining escaping logic. In addition, it provides Escapable, an augmentation trait for facilitating wrapping values in Escaped.

The wrapping approach allows escaping arbitrary values implementing Display without the need to buffer them.

Example

use rescue_blanket::Escapable;
println!("foo=\"{}\"", "bar=\"baz\"".escaped_with(char::escape_default));

License

This work is provided under the MIT license. See LICENSE for more details.

lib.rs:

Escape values while they are being formatted

When processing data, and particularly when forwarding data, in the form of character sequences (strings, streams, ...), one needs to escape certain characters or constructs which have some special meaning in the format. This crate provides [Escaped], a wrapper implementing [Display] such that the inner value is automatically escaped when formatted.

The escaping logic can be customized via the [Escaper] trait, or by supplying an FnMut(char) -> Display + Clone.

Rather than importing [Escaped] directly, users are encouraged to import [Escapable] instead. This convenience trait augments all [Sized] [Display] types with functions wrapping the value in an [Escaped] (for unsized types, a reference to the value may be used instead):

use rescue_blanket::Escapable;
println!("foo=\"{}\"", "bar=\"baz\"".escaped_with(char::escape_default));

Why using rescue_blanket?

There are a number of crates already for escaping strings, and there are already str::escape_default, escape_debug and escape_unicode, so why yet another library?

These functions, and the libraries I found, only work well if the values you need to escape are already accessible as [str]. However, sometimes your values are more complex, maybe recursive, and you may not want put escaping logic inside their [Display] implementation. After all, the need for escaping arises from the context the value is formatted in, not from the value itself.

You could always format complex values into some buffer (e.g. [String]) and apply escaping on the result, but that requires the additional buffer and you may want to avoid that. Depending on the [Escaper], the use of [Escaped] does not involve any additional buffering.