thorf

Interpreter for a massively simplified version of Forth.

I originally wrote this as a solution to an exercism.io exercise, but had so much fun that I decided to take it a bit further.

Supported "words"

Basic integer arithmetic operations:

• +: add last two items
• -: subtract last item from second to last item
• *: multiply last two items
• /: divide second to last item by last item

Stack manipulation operations:

• DUP: duplicate the last item
• DROP: remove the last item
• SWAP: swap the order of the last two items
• OVER: duplicate the second to last item

Output:

• .: print the last item as an integer
• .s: print the stack without consuming it
• EMIT: print the last item as a unicode character

It also supports defining new words at runtime:

: word-name definition ;

Executable

$ go install github.com/fordhurley/thorf/cmd/thorf
$ thorf -e "1 2 + ."
3
$ thorf testdata/helloworld.fs
Hello, world!
$ echo "6 4 - ." | thorf
2