Simple Pascal Interpreter

This is my attempt at following the Let's Build A Simple Interpreter series. Since I like C++ but probably never will write C++ professionally (full-time C# web developer) I decided that C++ should be a good exercise for me.

Implemented language features:

• Built-in types
  • BOOLEAN
  • INTEGER
  • REAL
  • STRING (TODO: Currently leaks memory because the string pool is not cleaned up when strings are no longer used)
• Variable assignment
  • Type conversion
• Operators
  • Standard math operators
  • Comparison operators (Just eq for now)
  • String concatenation
  • Unary operators
• Control flow
  • If / Else
    • Single line
    • Multi-line
• Semantic analysis
• Comments
• Procedures
  • Parameter support
  • Built-in procedures
    • writeln
• Functions
  • Parameter support
  • Built-in functions
    • random

Implemented interpreter features:

• REPL mode
• File mode
• Pinpointing the cause of an issue, for instance:

In a call to procedure writeln too many arguments have been provided

           writeln('a = ', a);
        -------------------^

Technical:

• Written in C++17
• Minimum dependency on Win32 API if any
• Warnings as errors, SDL checks on
• About 60 unit tests written in C++ / Catch

Sample program:

PROGRAM Part10;
VAR
   number     : INTEGER;
   a, b, c, x : INTEGER;
   y          : REAL;

BEGIN {Part10}
   BEGIN
      number := 2;
      a := number;
      b := 10 * a + 10 * number DIV 4;
      c := a - - b
   END;
   x := 11;
   y := 20 / 7 + 3.14;
   writeln('hello world!');
END.  {Part10}