English Programming Language

Write some sentences and watch the interpreter try to understand what you meant.

Introduction

The goal of this project is to make a language that is as similar as possible to plain English. Natural language is ambiguous, so we apply a series of rules and constraints to it. With them, we end up with a language that looks like English, but that is stable enough to be understood by a computer.

Of course, nothing can stop you from writing code that is obfuscated or not similar at all to a text in English, but it's up to you to write EPL programs in a readable way.

Here is a snippet with some sentences that the interpreter can understand:

Let L be the list from 0 to 5.
Add 1 to each number in L.
Print each element in L plus 2.

Here is the full documentation for the language's syntax.

Here is the documentation for the language's prelude.

Here are some examples of EPL programs.

Features

• Spaces are allowed in variable and function names.
• Arguments can be passed by value or by reference.
• A strong type system is used for disambiguation.
• Garbage collector.
• Loops, conditionals, and try-catch.
• Optional function parameter names, with aliases generation.

Work in progress

• Finding a more natural syntax for specifying function return types.

Possible improvements:

• Importing other files as libraries.
• Records.
• Interactive environment.
• Special variable it for referencing the result of the previous sentence.
• Built-in filtering with callbacks as arguments.
• Allowing user-defined generic functions.

Usage

Requirements: Stack

To run a program, for example program.epl, simply use:

stack run -- program.epl

The -h or --help option displays usage help.

The -s or --silent option runs the interpreter without printing warnings or success messages.