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Autumn

Build Status codecov license platform

An easy interpreter to learn.

example

Features

  • Modern C++ style(Based on C++17)
  • Support Linux and MacOS
  • Full comments
  • Support debug in repl

example2

  • Higher-order functions supported

example3

  • Closure supported

example4

  • ...

Quick Start

Install GCC8

  • Centos
$ yum install readline-devel.x86_64
$ yum install -y devtoolset-8-toolchain
$ scl enable devtoolset-8 bash
  • Ubuntu
$ sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
$ sudo apt-get update -qq
$ sudo apt-get install -qq g++-8
$ apt-get install lib64readline-dev
$ export CXX="g++-8"
$ export CC="gcc-8"

Build & Test

$ make

Repl

  • lexer mode
$ ./autumn lexer
  • parser mode
$ ./autumn parser
  • debug in parser mode
$ DEBUG_AUTUMN=1 ./autumn parser
  • eval mode
$ ./autumn eval

Demo

An example below showing how to write quick sort.

  • You need a filter function
let filter = fn(arr, f) {
    let iter = fn(arr, accumulated) {
        if (len(arr) == 0) {
            accumulated
        } else {
            let e = if (f(first(arr))) {
                push(accumulated, first(arr));
            } else {
                accumulated
            }
            iter(rest(arr), e);
        }
    };
    iter(arr, []);
};
  • QuickSort
let quickSort = fn(arr) {
    if (len(arr) == 0) {
        return arr;
    } else {
        let head = first(arr);
        let smaller = filter(rest(arr), fn(x) { x <= head });
        let bigger = filter(rest(arr), fn(x) { x > head });
        return quickSort(smaller) + [head] + quickSort(bigger);
    }
}
let a = [4,5,3,4,6,6]
quickSort(a)

example5

Contributor

Allen.

License

This project maintained under BSD 2.

Contact

QQ Group for Autumn: 985682510 QQ Group for Linuxers: 610441700

References