The Alpha Compiler

Source for the Alpha language compiler and all its components.

Summary

• ⭐ Examples
• ☘️ Features
• 🔌 Installation & Usage
• 📑 Components
• 🖥 Lexer-Parser
• 🎨 Vim
• 📚 Documentation
• 👋 References & Thanks

Examples

See all examples here.

Primes

* 1
* 2
* 3
* 5
* 7
* 11
* 13
* 17
* 19
* 23
* 29
* 31
* 37
* 41

Fibonacci

fib( 1 ) = 1
fib( 2 ) = 2
fib( 3 ) = 3
fib( 4 ) = 5
fib( 5 ) = 8
fib( 6 ) = 13
fib( 7 ) = 21
fib( 8 ) = 34
fib( 9 ) = 55
fib( 10 ) = 89

Alpha (Ascii Art banner)

Note that code in the preview is minimized (click on the image to view the full code).

Using sed to replace 0s and 1s this snippet outputs this :

| #..##..#....###..# |
| #.#..#.#....#..#.# |
| #.####.#....###..# |
| #.#..#.####.#....# |

| #.#..#..##..# |
| #.####.#..#.# |
| #.####.####.# |
| #.#..#.#..#.# |

Features

Written in Julia, Alpha is a compiled, statically typed procedural language. Furthermore, this language supports recursion and the compiler is multipass (functions can be called before being declared).

In addition to the compiler, a lexer-parser generator which works like flex / bison is included.

Alpha is inspired by Julia and Python for the syntax, though it supports only integers for variables.

See a brief syntax overview.

Installation & Usage

Installation

To install Alpha, first install dependencies and follow these instructions :

julia
]
add https://github.com/Cc618/Alpha

After this, you can test whether the package is installed with this command :

julia -e "import Alpha; Alpha.alphamain()" help

Note that this step can take few seconds the first time the module is imported due to precompilation.

Usage

To use Alpha, import it and run alphamain that interpretes program arguments.

julia -e "import Alpha; Alpha.alphamain()" <ARGS>

You might want to type only alpha <ARGS> instead of this long command. To do so, you can install Alpha within /usr/bin with this script (requires root privileges) :

sudo ./install.sh

Otherwise, without root privileges you can create an alias and add it to your bashrc :

alias alpha='julia -e "import Alpha; Alpha.alphamain()"'

Here is the list of all commands :

Command	Result
alpha <file>.alpha	Compile <file>.alpha to <file>
alpha run <file>.alpha	Run <file>.alpha
alpha build <file>.alpha	Build <file>.o object file
alpha generate <file>.alpha	Generate <file>.asm assembly code
alpha [help|-h|--help]	Show help

Dependencies

Alpha targets Linux machines. Moreover, it relies on some binaries :

• make
• gcc
• nasm
• julia

Alpha has been tested on Manjaro and Arch Linux (december 2020) with Julia 1.5.3.

Notes for developers

To test Alpha, you can use the Makefile instead of recompiling the package for each test :

make
julia src/Alpha.jl <ARGS>

To build the package in local :

julia
]
add /abspath/to/Alpha

Note that dev can be used instead of add.

Components

• alphalib : The Alpha standard library.
• docs : Project's documentation.
• examples : Some Alpha programs.
• parser : The lexer and parser generator.
• src : The Alpha Compiler.
• vim : Plugin for syntax highlighting.

Lexer-Parser

A lexer and parser generator have been created.

The lexer supports custom regexes, the syntax is simple because Alpha's syntax is pretty easy.

The parser is an SLR(1) parser, it handles location detection to display meaningful errors.

Links

• Calculator example.
• Parser documentation.
• Lexer documentation.

Vim

The vim folder contains a plugin for Vim syntax highlighting, the script install.sh can be used to install it or any Vim plugin manager can be used.

Vundle installation :

" In the plugin section of your .vimrc
Plugin 'Cc618/Alpha', {'rtp': 'vim/'}

Source your .vimrc or restart Vim and then type :

:PluginInstall

Documentation

You can see all documentation pages here.

References & Thanks

This project was made with the help of this amazing book. Thanks Douglas Thain for posting freely these resources online.