Piethon

A basic python-like interpreter in C++ using flex and bison.

Requirements

A C++ compiler, Flex, and Bison.

Build Instructions

To build the project, run make.

Running the Interpreter

To run the interpreter accepting input from STDIN, run ./piethon To use a source file, run ./piethon filename

Sample programs can be found in the 'test' directory.

Features

This program aims to be an experiment with Flex, Bison, and Abstract Syntax Trees, rather than any sort of Python replacement. However, the following (small) functionality exists.

• Integer and floating point expressions

• If/Else blocks

• Variables (with both global and function scope)

• Functions (including nested functions and recursion)

• While loops

• Arithmetic Operators (+, -, *, /, %, ^)

• Assignment operators (+=, -=, *=, /=, ^=, %=)

• Increment/Decrement operator (++/--, cannot currently be used in expressions)

• Comments (beginning with a '#')

• Condiional statements (<, >, <=, >=, ==, !=)

• Line-number reporting for both syntactic and semantic errors

• Different return codes for semantic/syntactic errors. The interpreter will return the following values:

  • 0: successful parse and run
  • 1: syntax error
  • 2: semantic error
  • 3: other error (ex: source file not found)

• Function calls as statements. Simply "f()" is a valid program statement. If main() is defined, it will automatically be invoked.

• Smart exception handling and error messages for runtime errors, such as:

  • unbound identifier
  • undefined function
  • function signature mismatch
  • div/mod by zero
  • return statement outside of function body