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Show HN: Forsh – A Unix shell embedded in Forth

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Re: Show HN: Forsh – A Unix shell embedded in Forth

#3

Post by spc476 »

I did a Forth-like Unix shell in college (mid 90s) as a class project [1]. The differences I see from mine are:

1) I made Unix commands a first-class variable type. You could create a single Unix command and store it into a variable. You could also set up several commands as a pipe, and save that into a variable.

2) redirection and pipes are more Forth in style. Much like adding two values:

    2 3 +
To create a pipe, you create the two commands and then pipe them:

    cmd1 cmd2 |
I'm looking over the code, and I don't think I finished redirection to tell the truth, but I can see it being easy to add it like:

    cmd1 "filename" |
since variables are typed in my Forth-like language.

It was a fun project to write (it even included history!) but as a practical shell? Not so much. The syntax left much to be desired for an interactive shell.

[1] Unix systems programming. The class project was a Unix shell. I had, by that time, already written a Forth-like programming language on my own [2], which meant I could do the advanced shell (programmable) instead of the simple shell (command execution and redirection only).

[2] I was seriously interested in Forth at the time.

Re: Show HN: Forsh – A Unix shell embedded in Forth

#10

Post by rijoja »

unixhero wrote: post #9
1024core wrote: post #4

Didn't the old Sun workstations boot into a Forth interpreter?

Was / is Forth good and useful? Bonus; is it fun?

It's fun to learn, and one of the first interpreted environments. What it enables is quick development on platforms with modest resources! Instead of compiling and executing you could develop quickly! Haven't used it for anything more than to do some examples in some tutorial.

One thing that's nice about the language is that it's the simplest language you can implement on your own without going insane!

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