forth-stuff

This repo includes some forth programming knowledge I wanted to jot down because it helps understand how bitcoin script works.

Install

Using the package from https://github.com/h8gi/fifth (a forth interpreter that runs as a command line repl):

go get github.com/h8gi/fifth

The fifth executable should be in $GOPATH/bin/fifth after go get.

Usage

Clone this repo, then you can...

1. Run example forth programs

Make examples.sh executable then build the project and run ./examples.sh.

chmod u+x examples.sh
go build main.go
./examples.sh

You can modify ./examples.sh to add additional programs to the output.

2. Run interactive fifth repl

main.go is an implementation of the fifth repl run as a go program instead of a binary in $GOPATH. If installed correctly through go get in the above Install section then you should be able to run the fifth program in terminal.

Make sure your $GOPATH is part of your $PATH bash environment variable, then run:

fifth

Alternatively you can go run main.go to access the repl through the h8gi/fifth library.

Why?

This repo should help you understand the reverse polish notation language that Bitcoin script is modeled after. That language is called forth. Using the example script in this repo or by using the fifth repl you can try out different forth programs to better understand how Bitcoin script works.

Follow along with this YouTube video or this chapter of Andreas M. Antonopoulos's Bitcoin Book and run the fifth repl interactively to see how it works:

https://www.youtube.com/watch?v=8FeAXjkmDcQ