The PL/0 Language Tools serve as an example of how to construct a compiler. The language 'PL/0' was originally introduced in the book "Algorithms + Data Structures = Programs", by Niklaus Wirth in 1975.
This project includes a full stack of tools designed for educational purposes to learn about compilers, interpreters and virtual machines. Each component can be executed independently and is typically between 100-300 lines of code.
It is designed to be clear and concise at the expense of performance. It is easy to extend and modify, e.g. adding new syntax constructs or machine instructions.
Install ply:
sudo easy_install ply
Then, simply download the files pl0_*.py and run them.
Here is a full example using the interpreter:
$ ./pl0_interpreter.py < examples/fibonacci.pl1
1
1
2
3
5
8
13
21
34
55
89
144
233
377
610
987
1597
2584
4181
6765
10946
-- Stack Frame --
Constants: {'K': 20}
Variables: {'count': 21, 'k': 17711, 'm': 17711, 'n': 28657}
Procedures: {}
If you want to see a abstract syntax tree of your program, use the pl0_graphviz.py command:
./pl0_graphviz.py < examples/fibonacci.pl1
A sample graph is included in the examples directory.
For more advanced usage, including documentation on individual components, please see the online documentation.
Recent development adds several new compiler targets. I'm interested in the possibility of cross compiling PL/0 to other languages; most of my work on this targets this.
I (Charles) am working on cross compilers for several stack based languages, including Retro, Parable, and ANS FORTH.
Copyright, 2012, by Samuel G. D. Williams. http://www.codeotaku.com
Copyright, 2012, by Michal J Wallace. http://www.michaljwallace.com/
Copyright, 2012, 2016, 2017 by Charles Childers http://forthworks.com/
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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