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https://github.com/google/skylark

Skylark in Go: the Skylark configuration language, implemented in Go [MOVED to go.starlark.net]
https://github.com/google/skylark

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Skylark in Go: the Skylark configuration language, implemented in Go [MOVED to go.starlark.net]

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README 

        



# Skylark in Go



**Skylark is now called Starlark.  The project has moved to [go.starlark.net](https://go.starlark.net).**



This is the home of the _Skylark in Go_ project.

Skylark in Go is an interpreter for Skylark, implemented in Go.



Skylark is a dialect of Python intended for use as a configuration language.

Like Python, it is an untyped dynamic language with high-level data

types, first-class functions with lexical scope, and garbage collection.

Unlike CPython, independent Skylark threads execute in parallel, so

Skylark workloads scale well on parallel machines.

Skylark is a small and simple language with a familiar and highly

readable syntax. You can use it as an expressive notation for

structured data, defining functions to eliminate repetition, or you

can use it to add scripting capabilities to an existing application.



A Skylark interpreter is typically embedded within a larger

application, and the application may define additional domain-specific

functions and data types beyond those provided by the core language.

For example, Skylark was originally developed for the

[Bazel build tool](https://bazel.build).

Bazel uses Skylark as the notation both for its BUILD files (like

Makefiles, these declare the executables, libraries, and tests in a

directory) and for [its macro

language](https://docs.bazel.build/versions/master/skylark/language.html),

through which Bazel is extended with custom logic to support new

languages and compilers.



## Documentation



* Language definition: [doc/spec.md](doc/spec.md)



* About the Go implementation: [doc/impl.md](doc/impl.md)



* API documentation: [godoc.org/github.com/google/skylark](https://godoc.org/github.com/google/skylark)



* Mailing list: [skylark-go](https://groups.google.com/forum/#!forum/skylark-go)



* Issue tracker: [https://github.com/google/skylark/issues](https://github.com/google/skylark/issues)



* Travis CI: ![Travis CI](https://travis-ci.org/google/skylark.svg) [https://travis-ci.org/google/skylark](https://travis-ci.org/google/skylark)



### Getting started



Build the code:



```shell

$ go get github.com/google/skylark/...

$ go build github.com/google/skylark/cmd/skylark

```



Run the interpreter:



```

$ cat coins.sky

coins = {

  'dime': 10,

  'nickel': 5,

  'penny': 1,

  'quarter': 25,

}

print('By name:\t' + ', '.join(sorted(coins.keys())))

print('By value:\t' + ', '.join(sorted(coins.keys(), key=coins.get)))



$ ./skylark coins.sky

By name:	dime, nickel, penny, quarter

By value:	penny, nickel, dime, quarter

```



Interact with the read-eval-print loop (REPL):



```

$ ./skylark

>>> def fibonacci(n):

...    res = list(range(n))

...    for i in res[2:]:

...        res[i] = res[i-2] + res[i-1]

...    return res

...

>>> fibonacci(10)

[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

>>>

```



When you have finished, type `Ctrl-D` to close the REPL's input stream. 



### Contributing



We welcome submissions but please let us know what you're working on

if you want to change or add to the Skylark repository.



Before undertaking to write something new for the Skylark project,

please file an issue or claim an existing issue.

All significant changes to the language or to the interpreter's Go

API must be discussed before they can be accepted.

This gives all participants a chance to validate the design and to

avoid duplication of effort.



Despite some differences, the Go implementation of Skylark strives to

match the behavior of the Java implementation used by Bazel.

For that reason, proposals to change the language itself should

generally be directed to the Bazel team, not to the maintainers of

this project.

Only once there is consensus that a language change is desirable may

its Go implementation proceed.



We use GitHub pull requests for contributions.



Please complete Google's contributor license agreement (CLA) before

sending your first change to the project.  If you are the copyright

holder, you will need to agree to the

[individual contributor license agreement](https://cla.developers.google.com/about/google-individual),

which can be completed online.

If your organization is the copyright holder, the organization will

need to agree to the [corporate contributor license agreement](https://cla.developers.google.com/about/google-corporate).

If the copyright holder for your contribution has already completed

the agreement in connection with another Google open source project,

it does not need to be completed again.



### Stability



We reserve the right to make breaking language and API changes at this

stage in the project, although we will endeavor to keep them to a minimum.

Now that the project's long-term name ("Starlark") has been decided,

we plan to copy this repository to github.com/google/starlark and

change the canonical import path for all packages to starlark.net/starlark.

The current github.com/google/skylark repository will be frozen.

Once the Bazel team has finalized the version 1 language specification,

we will be more rigorous with interface stability.



### Credits



Skylark was designed and implemented in Java by

Ulf Adams,

Lukács Berki,

Jon Brandvein,

John Field,

Laurent Le Brun,

Dmitry Lomov,

Damien Martin-Guillerez,

Vladimir Moskva, and

Florian Weikert,

standing on the shoulders of the Python community.

The Go implementation was written by Alan Donovan and Jay Conrod;

its scanner was derived from one written by Russ Cox.



### Legal



Skylark in Go is Copyright (c) 2017 The Bazel Authors.

All rights reserved.



It is provided under a 3-clause BSD license:

[LICENSE](https://github.com/google/skylark/blob/master/LICENSE).



The name "Skylark" is a code name of the Bazel project.

The Bazel team plans to rename the language to "Starlark" to reflect its

applicability to projects unrelated to Bazel.



Skylark in Go is not an official Google product.