czaks / cfvm

A toy lightweight interpreted stack-based virtual machine with implementation in Ruby

CFVM

A toy stack-based interpreted virtual machine. Actually, stack of stacks based.

It aims to be as minimal as possible, so that it would be easy to implement.

We try to offload as much as possible to a stdlib.

CFVM runs a language called CF, which is inspired by Forth and is similar to Joy. It uses Reverse Polish Notation.

Syntax

The CF language is syntaxless. It is lexed just by split(/\s+/).

Types

• Symbol: :symbol
  • Symbol is an immutable string, just like a Ruby symbol.
• Integer: 6
  • Integers can be manipulated just like in every modern language.
• Code block: [ 2 7 + ]
  • Code blocks can be executed using exec
• Stack: ( 1 2 3 )
  • Stacks can be concatenated using +
  • Stacks can be compared using ==
  • Stacks can be entered using enter and left using exit.

Environment

An environment is a map of symbols. You can assign code block or a variable in the following ways:

• [ + ] :plus def
• 5 :five def

...or using a reversed notation:

• :plus [ + ] defun
• :five 5 defun

Environment can be called simply:

• five five plus (would yield 10)

Environment members can be overloaded at any time.