AwesomePascal

Another PL/0 language (https://en.wikipedia.org/wiki/PL/0) compiler and debugger that is written in C++.

Introduction

This code came from my undergrad course project for compiler principles in 2015. The code quality is beyond horrible but it's some of my earliest big projects.

Architecture

• The compiler uses SLR(1) parsing. The grammar is hard-coded in the form of an LR parsing table (states) and the FOLLOW set (follows) which is initialized in initStates() function.
• The compiler was written from the ground up without any third-party libraries except the standard C++ library.
• It contains:
  • A lexer (GETSYM() function) that processes the input into tokens and literals while constructing a symbol table
  • A parser (BLOCK() function) that uses shift/reduce-parsing to generate the target code (pseudo-assembly)
  • An interpreter (INTERPRET() function) that executes the pseudo-assembly code.

Build

Supported Environments:

• MSVC project: AwesomePascal.vcxproj
• GNU C++/Clang: compile AwesomePascal.cpp directly

Examples

• InsertionSort.pas: A simple program that takes 5 integers and sorts them in descending order.
• NumericExpr.pas: A simple program that contains numerical expressions and control flow.

Usage

$ g++ -O3 -DNDEBUG AwesomePascal.cpp -o BP
$ ./BP InsersionSort.pas