Aurora 12SDD PseudoExe Language Project

A project for Year 12 Software Design and Development which will allow students to explore:

• Machine code and the CPU
• Metalanguages
• Translation, specifically:
  • lexical analysis including token generation
  • syntactical analysis including parsing
  • code generation

Motivation

Theoretical discussion of metalanguages, and lexical and syntactical analysis can be quite dry and often the importance is lost on students who wonder why the hell they are learning this stuff that they will never use. The intent here is to introduce these concepts through the challenge of developing their own executable language. It also addresses the issue that a syntactically rigid pseudocode like that specified in the SDD Course Specifications defeats the whole purpose of pseudocode (don't get me started)

The Task

The initial task is to write an executable version of pseudocode that can print out the fibonacci series. The PseudoExe scripts will have a suffix of *.pse. The script for the ultimate goal is fibonacci.pse is:

BEGIN Fibonacci

LET currentNumber = 0

DISPLAY currentNumber

LET prevNumber = currentNumber
LET currentNumber = prevNumber + 1

DISPLAY currentNumber

FOR LET counter = 0 TO 20 STEP 1
    LET tempNumber = currentNumber
    LET currentNumber = currentNumber + prevNumber
    LET prevNumber = tempNumber
    DISPLAY currentNumber
NEXT counter

END Fibonacci

Resources

This project is very heavily based on Marcelo Andrade's work Writing your own programming language and compiler with Python

You will need to install the following:

• LLVMLite A lightweight LLVM python binding for writing JIT compilers

pip install llvmlite

• RPLY A pure Python parser generator

pip install rply

• LLC An LLVM static compiler
• GCC or other linking tool

Other useful references

• PLY documentation
• Using RPython and RPly to build a language interpreter, part 1
• RPLY ReadTheDocs

NOTES

ATM this project is compLETely untested - we are on this journey together

TODO