Serpentine

Precise navigation of paths

Serpentine is a small library for handling the abstract notion of paths, distinguishing between
relative and absolute forms, rooted on some value. This may be useful for representing paths on a
filesystem, resources on an HTTP server, descendants in a family tree, or many other concepts which
follow a hierarchical pattern.

Features

representations of hierarchical paths
designed for extension and use in many concrete contexts
distinguishes between absolute and relative paths

Availability

Getting Started

The type Root defines a "root", beneath which any number of possible Path instances may exist in
a hierarchy, and the methods parent, ancestor and / may be used to navigate between them. For
abstract paths, the value Base can serve as a root node for a path hierarchy.

Here are some examples:

val crustaceans = Base / "eukaryota" / "animalia" / "arthropods" / "crustaceans"
val arthropods = crustaceans.parent
val animalia = crustaceans.ancestor(2)

Paths may be further distinguished as Path.Relative or Path.Absolute, where a Relative may
be converted into an Absolute by calling the Path#absolute method, and passing an absolute path
to which the relative path should be considered relative to. The result is typed as Path.Absolute.

Path objects, whether absolute or relative, serialize with toString according to the delimiters
in their root, which are defined in terms of a base name (for example, / or classpath:) and a
separator (for example, \, / or .).

Any implementation of Root should define these values, prefix and separator, respectively. For
example, the definition,

object Domain extends Root(prefix = "", separator = ".")

would ensure that,

Domain / "www" / "example" / "com"

would serialize to the string "www.example.com".

Note that the separator is not included between the prefix and the first path element when
serializing, so may need to be included in the prefix value itself.

Other Methods

The method ++ can add a Relative path to an Absolute path, and return a new Absolute path.

Similarly, Absolute#relativeTo takes another Absolute path and returns a Relative instance
that, when applied with ++ to the first path, produces the second path.

The Absolute#conjunction method will find the closest common parent of the path and its parameter.

Note that Paths are not aware of their children, so there is no children method, but this may be
provided by individual implementations.

Exceptions

Many operations on Paths may attempt (directly or indirectly) to access the parent of the root.
This is not possible, and if this happens, a RootBoundaryExceeded exception will be thrown.

Generic relative paths

Given that a relative path is (by definition) not attached to any particular root, all instances of
Root#Path.Relative inherit from GenericRelative which gives users the choice, when implementing
APIs that accept relative paths, between accepting any kind of relative path (regardless of its
origin) and accepting just those originating from a particular root.

Status

Serpentine is classified as fledgling. For reference, Soundness projects are
categorized into one of the following five stability levels:

embryonic: for experimental or demonstrative purposes only, without any guarantees of longevity
fledgling: of proven utility, seeking contributions, but liable to significant redesigns
maturescent: major design decisions broady settled, seeking probatory adoption and refinement
dependable: production-ready, subject to controlled ongoing maintenance and enhancement; tagged as version 1.0.0 or later
adamantine: proven, reliable and production-ready, with no further breaking changes ever anticipated

Projects at any stability level, even embryonic projects, can still be used,
as long as caution is taken to avoid a mismatch between the project's stability
level and the required stability and maintainability of your own project.

Serpentine is designed to be small. Its entire source code currently consists
of 413 lines of code.

Building

Serpentine will ultimately be built by Fury, when it is published. In the
meantime, two possibilities are offered, however they are acknowledged to be
fragile, inadequately tested, and unsuitable for anything more than
experimentation. They are provided only for the necessity of providing some
answer to the question, "how can I try Serpentine?".

Copy the sources into your own project

Read the fury file in the repository root to understand Serpentine's build
structure, dependencies and source location; the file format should be short
and quite intuitive. Copy the sources into a source directory in your own
project, then repeat (recursively) for each of the dependencies.

The sources are compiled against the latest nightly release of Scala 3.
There should be no problem to compile the project together with all of its
dependencies in a single compilation.
Build with Wrath

Wrath is a bootstrapping script for building Serpentine and other projects in
the absence of a fully-featured build tool. It is designed to read the fury
file in the project directory, and produce a collection of JAR files which can
be added to a classpath, by compiling the project and all of its dependencies,
including the Scala compiler itself.

Download the latest version of
wrath, make it
executable, and add it to your path, for example by copying it to
/usr/local/bin/.

Clone this repository inside an empty directory, so that the build can
safely make clones of repositories it depends on as peers of serpentine.
Run wrath -F in the repository root. This will download and compile the
latest version of Scala, as well as all of Serpentine's dependencies.

If the build was successful, the compiled JAR files can be found in the
.wrath/dist directory.

Contributing

Contributors to Serpentine are welcome and encouraged. New contributors may like
to look for issues marked
beginner.

We suggest that all contributors read the Contributing
Guide to make the process of contributing to Serpentine
easier.

Please do not contact project maintainers privately with questions unless
there is a good reason to keep them private. While it can be tempting to
repsond to such questions, private answers cannot be shared with a wider
audience, and it can result in duplication of effort.

Author

Serpentine was designed and developed by Jon Pretty, and commercial support and
training on all aspects of Scala 3 is available from Propensive
OÜ.

Name

A path which is serpentine may be a challenge to navigate, which is where Serpentine can help.

In general, Soundness project names are always chosen with some rationale,
however it is usually frivolous. Each name is chosen for more for its
uniqueness and intrigue than its concision or catchiness, and there is no
bias towards names with positive or "nice" meanings—since many of the libraries
perform some quite unpleasant tasks.

Names should be English words, though many are obscure or archaic, and it
should be noted how willingly English adopts foreign words. Names are generally
of Greek or Latin origin, and have often arrived in English via a romance
language.

Logo

The logo shows a serpentine section of river, meandering.

propensive/serpentine