A Stack Based Language in Rust

This project is an experimental cross between a stack-based language like Forth and an array-based language like APL.

Array-based languages like APL typically make heavy use of infix operators. This project gives a user the ability to write APL-like code in a reverse-polish notation which can make it easier to express a program from left to right.

One goal in this project is to demonstrate writing Rust in a pure functional style with functional-but-in-place mutation facilitated by the ownership system.

Usage

cargo run - this will open a prompt where you can write a series of numbers and "words" that will be executed after hitting enter. The output will be "the stack" after executing the line. Enter a blank line to exit.

Example

> 1 2 +
3

> 1 2 3
3
2
1

> 1 2 3 |
[[1.0, 2.0, 3.0,]]

> 1 2 3 | 5
5
[[1.0, 2.0, 3.0]]

> 1 2 3 | 5 *
[[5.0, 10.0, 15.0]]

> 1 2 3 | 5 * sum
30

Available builtin words

• + Addition
• - Subtraction
• * Multiplication
• / Division
• | Create array from scalers at the top of the stack
• negate, neg Negate
• reverse, rev Reverse array
• length, len Length of array
• sum Sum of array
• product, prod Product of array
• iota Produce array that is a range from 1 to n
• right Copy first element on the stack
• left Copy second element on the stack
• commute Swap the first and second element on the stack

Roadmap

• Refactor
• Booleans
• 2 Dimensions
• Higher order operators
• Custom words (functions)
• File interpreter