Awesome

Mirror closed because of 2FA, now only at https://codeberg.org/anaseto/goal

Goal

Goal is an embeddable array programming language with a bytecode interpreter, written in Go. It provides both a command line intepreter (that can be used in the REPL), and a library interface. The core features are mostly there and tested, so Goal is usable both for writing useful short scripts and playing with the REPL. User testing and bug reports are welcome!

Like in most array programming languages, Goal's builtins vectorize operations on immutable arrays, and encourage a functional style for control and data transformations, supported by a simple dynamic type system with little abstraction, and mutable variables (but no mutable values).

It's main distinctive features are as follows:

• Syntax inspired mainly from the K language, but with quite a few deviations. For example, backquotes produce Go-like raw strings instead of symbols, rx/\s+/ is a compile-time regular expression literal, and there is Perl-style string interpolation. On the other side, there are no tacit compositions, and digraph operator verbs and adverbs are gone or done differently (except for global assignment with ::).
• Primitive semantics are both inspired from the ngn/k variant of the K language and BQN. For example, group by, classify, shifts, windows, binary search and occurrence count take after BQN's semantics, but free-form immutable arrays, dictionaries and adverbs take after K.
• Unlike in typical array languages, strings are atoms, and common string handling functions have been integrated into the primitives, including regular expression functions. Primitives acting on whole strings are Unicode-aware (like case-folding or Unicode properties in regexps).
• Error handling makes a distinction between fatal errors (panics) and recoverable errors which are handled as values.
• Integrated support for csv, json, time handling, and basic math.
• Simple IO: read/write files, run commands/pipes, open filehandles.
• Easily embeddable and extensible in Go.
• Array performance is quite decent, with specialized algorithms depending on inputs (type, size, range), and variable liveness analysis that reduces cloning by reusing dead immutable arrays (in code with limited branching). However, it is not a goal to reach state-of-the-art (no SIMD, and no bit booleans, fitting integers in arrays using either uint8 or int64 elements).

• Scalar performance is typical for a bytecode-compiled interpreter (without JIT), somewhat slower than a C bytecode interpreter: value representation is less compact than how it could be done in C, but Goal does have unboxed integers and floats.

If this list is not enough to satisfy your curiosity, have a look at the why section of the FAQ. You can also read the Credits.md to know about main inspiration sources for the language. Last, but not least, there are some implementation notes too.

Install

To install the command line interpreter, first do the following:

• Install the go compiler.
• Add $(go env GOPATH)/bin to your $PATH (for example export PATH="$PATH:$(go env GOPATH)/bin").

Then you can build the intepreter with:

go install ./cmd/goal

Alternatively, you may type go build -o /path/to/bin/goal ./cmd/goal to put the resulting binary in a custom location in your $PATH.

The goal command should now be available. Type goal --help for command-line usage.

Typing just goal opens the REPL. For a better experience using the REPL (to get typical keyboard shortcuts), you can install the readline wrapper rlwrap program (available as a package in most systems), and then use instead rlwrap goal.

Links

• Goal docs : work-in-progress documentation for Goal.
• vim-goal : vim files for Goal.
• APL Farm : chat about array languages.

Documentation

In addition to the work-in-progress documentation website, you might be interested in the Changelog changes between releases. The REPL help is also available in text form here at docs/help.txt.

Examples

A few short examples can be found in the examples and testdata/scripts directory. Because the latter are used for testing, they come along an expected result after a /RESULT: comment.

Also, various code generation scripts in the toplevel scripts directory are written in Goal.