Jackc is a simple, end-to-end compiler for the Jack programming language, which is the high-level, object-oriented programming language implemented as part of the Nand to Tetris course, as specified in the book The Elements of Computing Systems by Nisan and Shocken.
Unlike the approach taken in the book, which separates each stage of the compiler into different programs, Jackc is designed to transform .jack files all the way down to the Hack machine language, which can be eecuted by the Hack CPU specified in the book, or a suitable emulator.
You can install Jackc by running cargo install:
$ cargo install --git https://github.com/leocassarani/jackc
This will download the source code, compile it in release mode, and install the binary to $HOME/.cargo/bin/jackc (unless otherwise specified).
To compile a file containing Jack source code, simply run:
$ jackc Main.jack
This will produce a Main.hack file in the current directory. To write to a different filename, use the -o flag. To output to stdout, use the --stdout flag instead.
Jackc can compile any number of files or directories into a single Hack program. The Nand to Tetris course ships with eight .vm files that implement basic "OS" functionality such as drawing to the screen, reading from the keyboard, and a dynamic memory allocator. For any moderately complex Jack program, it's expected that some or all of the OS .vm files will be available to the compiler alongside the Jack source code. Jackc understands both .jack and .vm input files and will treat them equally.
Jackc can output one of three file formats:
- a
.hackfile containing the binary representation of the compiled CPU instructions as 16-bit ASCII ones and zeroes, one per line. Following the book's example, this is the default file format, and can also be specified using the--hackflag. - a
.binfile containing the binary, big-endian representation of the CPU instructions. This can be selected using the--binflag. - an
.asmfile containing the human-readable, assembly language translation of the CPU instructions. Use the--asmflag to specify this.
According to the specification in the book, execution of a Hack program is supposed to start at the Sys.init function, which forms part of the provided OS .vm files. However, the name of the program's start point can be overwritten using the --init flag, which can be useful if a non-standard OS is used. On the other hand, when compiling very simple .vm files that are not divided into separate functions, a --no-init flag can be given to start execution from the first line in the input file instead.
Jackc is licensed under the terms of the Apache 2.0 license. See LICENSE for details.