pseudocie

A Python-based interpreter for CIE A-Level Computer Science pseudocode, designed to parse and execute pseudocode programs following the Cambridge International Examinations 9618 specification. Built with Lark parser generator and an AST tree-walking interpreter.

⚠️ Important Note

This is a demonstration project that implements only a subset of the full CIE 9618 pseudocode specification. It supports basic language constructs like variable declarations, assignments, arithmetic operations, and input/output, but does not implement advanced features such as:

• Arrays and complex data structures
• Procedures and functions
• Control flow statements (IF/THEN/ELSE, loops)
• File handling operations
• Advanced string operations
• Error handling constructs

For the complete official specification, refer to the CIE 9618 Pseudocode Guide for Teachers.

Disclaimer: This project is not affiliated with, endorsed by, or connected to Cambridge International Education. It is an independent educational tool created for learning purposes.

Features

Currently supported pseudocode features:

• Data Types: INTEGER, REAL, STRING, BOOLEAN
• Variable Declarations: DECLARE variable : TYPE
• Constants: CONSTANT name = value
• Assignments: variable <- expression
• Arithmetic Operations: +, -, *, /, DIV (integer division), MOD
• Logical Operations: AND, OR, NOT
• Comparison Operations: >, <, >=, <=, =, <>
• Input/Output: INPUT variable, OUTPUT expression[, expression, ...]
• Comments: // comment text

Installation

1. Clone this repository:

git clone github.com/Steven-Gzc/pseudocie.git
cd pseudocie

2. Install dependencies (requires Python 3.8+):

pip install lark

Usage

Command Line Interface

Run a pseudocode file:

python cli.py path\to\file.cie

Additional options:

python cli.py path\to\file.cie -t        # Print parse tree
python cli.py path\to\file.cie -e        # Show environment after execution
python cli.py path\to\file.cie -d        # Dump parse tree to file

Example

python cli.py tests\hello.cie

Project Structures

pseudocie/
├── cli.py                 # Command-line interface
├── grammar.lark          # Lark grammar definition for CIE pseudocode
├── parse_utils.py        # Parsing utilities
├── cie_runtime/          # Runtime execution engine
│   ├── __init__.py
│   ├── environment.py    # Variable environment management
│   └── evaluator.py      # Expression evaluation and program execution
├── tests/                # Example pseudocode programs
│   ├── hello.cie
│   ├── expressions.cie
│   ├── div_mod.cie
│   └── constants_and_reals.cie
└── README.md

Limitations

This interpreter is a demonstration/educational tool and implements only basic pseudocode constructs. Missing features include:

• Uncommon Types: DATE, CHAR
• Control Structures: IF...THEN...ELSE, WHILE, FOR, REPEAT...UNTIL
• Subprograms: PROCEDURE, FUNCTION
• Data Structures: Arrays (ARRAY[1:10] OF INTEGER), records
• Advanced I/O: File operations, formatted output
• String Manipulation: Advanced string functions
• Type Checking: Runtime type validation
• Error Handling: TRY...EXCEPT blocks

Contributing

This project is intended as an educational demonstration. If you're working on extending CIE pseudocode support, consider:

Language Features

1. Adding control flow statements (IF/WHILE/FOR)
2. Implementing procedures and functions
3. Adding array and record support
4. Improving error messages and debugging features

Development Tools

5. Editor support (VS Code extension, syntax highlighting)
6. Auto-completion for CIE pseudocode keywords and constructs
7. Integration with popular IDEs
8. Hand-written paper OCR for digitizing pseudocode from exam papers
9. AI-generated exam-style questions and solutions for practice

License

This project is provided for educational purposes. Please refer to the official CIE documentation for complete pseudocode specifications.