Simple way to semantically require relative or absolute paths.

There are three main classes in this crate that have various constraints that are validated by their constructors. See try_new on each of these classes.

Each set of constraints has a *Path and *PathBuf variant, mirroring what is in the standard lib:

• RelativePath / RelativePathBuf: These paths must not start with /
• AbsolutePath / AbsolutePathBuf: These paths must start with a / and be a complete path.
• CombinedPath / CombinedPathBuf: These paths may be either a relative or absolute one.

# Cargo.toml
[dependencies]
paths = { git = "https://github.com/nataliejameson/paths", tag = "0.1.0" }

If the serde feature is enabled, a serialization / deserialization impl is made available that also validates path constraints on deserialization. If the diesel feature is enabled, a field type is added that allows serialization and deserialization in Diesel (ToSql/FromSql impls are provided)

For CombinedPath, CombinedPath::try_into_absolute() and CombinedPath::try_into_absolute_in_cwd() can be used to either return an absolute path, or resolve it against an absolute path if the inner data is a relative path.

Because FromStr is implemented, things like CombinedPathBuf can be used by clap.

Like Path, the *Path implementations are ~zero size containers over the inner Path reference object. It's similar in the case of PathBuf variants.

These types all can deref into Path like structs, so pretty much any stdlib functions should work with them.