Peelpreter 1.7.4

A interpreter written in Python for the language, Monkey

Contribution

This is my first time having a public repo on github so I'm not sure on how to go on about this. If anyone would like to contribute they are free to open issue, where i will discuss it with them.

Contribution Suggestions

Features on the features to add list, ones you think are missing and think should be there, etc. are all welcome.

Adding a issue for the feature fist, where things could be decided whether the feature is add-able to the language or interpreter, would be appreciated though.

Monkey

Peelpreter is a interpreter based on the language Monkey specified in the book Writing an Interpreter in Go. It is not designed to be the fastest implementation but instead a (mostly) readable one. I, personally don't find encapsulating every little function of a program in classes to be particularly readable. Hence, I have kept things bare-bone functions where I thought it made sense and used classes to encapsulate data like C-Structs and sometimes to store methods.

Features

Peelpreter supports all features of the canon implementation as well as some more. They are:-

1. Variables
2. If expressions
3. First-Class Functions
4. Loops. Eg: while and foreach
5. Closures
6. Array
7. Hash Map (Dictionary)
8. Builtin Functions
9. Array and Hash mutability
10. Improved puts function

Features Planned to be added

Some features which I wish for in a programming language are not present yet in this. Suppport for them will be slowly added as soon as type annotations are improved for the existing code base. They are:-

• Input function
• Type conversion
• While Loops
• For Loops
• Constants
• Add New Keyword list. This would cause loops to return an array of the results of the last expressions of each iteration of the loop instead of returning the result of the last expression of the last iteration of the loop.
• Add New Keyword To Make Objects Immutable
• Optional Parameters
• Structs
• Chaining variable assignments. E.g, let x = y = 7
• Import System
• Extension modules using Python

I might also added a Type Checker later on, but thats upto the future.

Changelog

• 1.6.0: Added input, num and str.
• 1.6.1: Fixed a bug which caused the interpreter to crash when a number was divided by zero
• 1.6.2: Fixed a bug with str which caused it to add double quotes (") around a String object each time it was called on it
• 1.7.0: Added while loops
• 1.7.1: Fixed crash from missing a = in let statements
• 1.7.2: Added foreach loops
• 1.7.3: Fixed unintended behaviour of variables not being modified globally
• 1.7.4: Added new keyword const for declaration of constants

Installation

For installation of the package run,

pip install peelpreter

Or if you would prefer to build and install yourself for a more up-to-date version, clone the repository and cd into it,

git clone https://github.com/GogiBoy102/Peelpreter.git
cd Peelpreter

then run,

python3 -m build

If build is not already installed onto the system then install it with,

pip install --upgrade build

After the build process ends, cd into dist and install the tar with,

cd dist
pip install peelpreter-<version>.tar.gz

And, voila! Peelpreter has been installed! For usage, follow the next section.

Usage

Peelpreter comes with a script called monkey which is the entry point for the interpreter and also the reccomended way for it to be used.

Files in monkey usually have the extension ".mon".

monkey, when executed with no command line arguments starts the REPL for Monkey. However, it can also execute files if the path to those files are supplied as a command line argument. The examples directory can be looked at for example programs writen in Monkey.

monkey (for starting a repl)

monkey /path/to/file (for running a file)

License

Peelpreter is license under the GNU General Public License version 3 or above with it also being copyrighted by Jeebak Samajdwar