1. Overview
-----------

Sprite is an implementation of the Curry programming language
(https://www.curry-lang.org/).  It is based
on an evaluation strategy called the Fair Scheme.  You can read about it at
http://web.cecs.pdx.edu/~antoy/homepage/publications/lopstr13/long.pdf.

In addition to command-line tools for compiling and running Curry programs, the
Python API provides access to a Curry interpreter, (JIT) compiler, and runtime.
Curry code modules can thus be imported directly into Python, enabling
hybrid applications that leverage the strengths of both languages.


2. Installation
---------------

On Linux, choose the path that fits your Python setup:

  1. Without a suitable Python, let the installer bring its own:

        curl -LsSf https://raw.githubusercontent.com/andyjost/Sprite/master/getsprite | sh

     For confirmation before each installation step:

        curl -LsSf https://raw.githubusercontent.com/andyjost/Sprite/master/getsprite-i | sh

     The script installs uv if needed, then a managed Python 3.11.4 or newer
     and currylang with its curry-frontend dependency, all in your home
     directory. It leaves the system Python alone and never uses sudo.
     Run it again to upgrade Sprite. To preview the plan, download the script
     and run sh getsprite --dry-run (or sh getsprite-i --dry-run).
     Add the commands to your PATH, including in your shell startup file:

        export PATH="$HOME/.local/bin:$PATH"

  2. With Python 3.11.4 or newer (through 3.15), install into your Python
     environment with pip:

        pip install currylang

     This also installs curry-frontend; uv is only needed by the script.

  3. Python developers can run a Curry source file or open the Curry REPL
     through the Python they installed into:

        python -m curry MyProgram.curry
        python -m curry

A C++ compiler (g++) is optional. Without one, new modules run interpreted;
see "Installing and running without a C++ compiler" in the documentation.

A conda recipe for linux-64 is under development under conda/.  It is not
published; conda/README.md describes it.

A developer who sets up a new machine runs scripts/setup-dev-machine.sh
--prefix DIR.  The script checks the apt packages and prints the apt command
when one is missing; it never runs sudo.  It installs PAKCS 3.4.1 and a conda
environment (conda/dev-environment.yml) under the prefix, links install/ and
object-root/ of the checkout into it, runs CMake and make stage in a
clean environment, and runs a smoke test.  Say --dry-run to print the plan
first.  The page "Developer Setup" of the documentation
(docs/source/DeveloperSetup.rst) describes the steps, the options, and the
layout of the prefix.


3. Running a Program
--------------------

Programs run with sprite-exec. In a staged source checkout, for example,
run this from the repository root:

        install/bin/sprite-exec examples/Peano.curry

The C++ backend runs a module interpreted until the compiled code is
ready, so an installation without a C++ compiler runs every program (see
the page "Installing and running without a C++ compiler" of the
documentation).

The numbered directories under examples/ hold runnable examples of Curry
programs and of Curry called from Python.  Each has a run script and a
README.  tests/unit_examples.py compares their output with expected.out
on the declared backends.  Example 19 is the successor to the retired
Flask blocks-world example.  examples/cxx/ and examples/Peano.curry are
support sources, without separate run scripts or expected-output tests.
See examples/README for the list.


4. Documentation
----------------

The user guide is published at https://andyjost.github.io/Sprite/ from the
master branch.  To build it yourself, run `make -C docs html` from the
repository root after `make stage`.  The output is written under
object-root/docs/html.  The sources are hosted at
https://github.com/andyjost/Sprite.


5. Contact and Bug Reporting
----------------------------

Sprite was developed and is maintained by Andy Jost (andy.m.jost@gmail.com).
Feel free to contact him with questions, bug reports, feature requests, and
other miscellania.  Direct general questions about Curry to the Curry mailing
list (curry@lists.RWTH-Aachen.DE).

If you find a bug, please report it.  The easiest way is to create a minimal
unit test decorated with ``unittest.expectedFailure``.  Further instructions on
developing and running tests can be found under tests/README.  Once you have
written the test, submit a pull request or send the diff by email.


6. Contributing to Sprite
-------------------------

Contributions are welcome!  For more information, see README.contrib.


5. License
----------

Sprite is distributed under the BSD 3-Clause License; see the LICENSE file.
The vendored Curry library under curry/lib carries its own BSD license and
notice.