#Runt

By Paul Batchelor

Runt is a quirky stack-based language and virtual machine.

Here are some features:

• Stack-based: heavily inspired by Forth
• Memory-pool allocation system: only one call to malloc/free needed!
• built-in parser and interpreter
• written in ANSI C
• simple API for defining new words
• Can be run inside of Polysporth plugin as a scheme-extension

#Compilation

To do a full compile of Runt and the Runt Polysporth extension run:

make

This assumes that Sporth is installed.

If you want to just compile the runt interpreter (and implicitly compile librunt):

make irunt 

To install run:

make install

Note that you do NOTE need sudo, since the files will be installed in ~/.runt/

To clean:

make clean

#Using Runt

Starting up irunt will get you to a prompt, where you can try things out.

"Hello world" in runt looks like this:

> "hello world!" say
hello world!

To make procedures, record mode must be turned on, which allows you to record to the cell pool. To return to interactive mode, you must stop:

> rec
Recording.
> : foo "runt is cool!" say ;
> stop
Stopping.
> foo
runt is cool!

Runt currently has supported for basic floating-point arithmetic. The "p" command pops the value from the stack and prints it.

> 1 3 + p
4
> 3 2 - p
1
> 10 3 / p
3.3333
> 12345 54321 * p
6.70593e+08

Some forth-like stack operations like swap and dup are also supported currently:

> rec : pow dup * ; stop
Recording.
Stopping.
> 5 pow p
25

#Plugins

Plugins are procedures written in C that can be dynamically loaded at runtime. They are an ideal way to "glue" other C-libraries together.

Example code for a plugin exists in plugin.c. To compile it, run:

make plugin.so

Once it is compiled, you can start up irunt in the directory it is in, and load it into the runt cell pool:

> "./plugin.so" dynload
> test
this is a plugin!