tinylisp

C implementation of a minimal lisp dialect described here

Build instructions

git clone https://github.com/dominicprice/tinylisp
cd tinylisp
mkdir build
cd build
cmake ..
make

Running

The interpreter should start by running the tinylisp executable in the build directory. A list of commands can be seen by passing --help (at the time of writing this is horribly incomplete, refer to the reference link above). It also accepts the optional switch --nobanner which prevents a startup copyright banner from being displayed. You may also specify a filename which it will accept as a script file, and evaluate each expression in the file displaying the results.

Example programs

Some example programs can be found in the tests directory.

Extended arithmetic operators

The builtins only support subtraction, but addition and multiplication can be implemented as follows

(d add
	(q (
		(a b)
		(s a (s 0 b))
	))
)

(d mul
	(q (
		(a b)
		(i b (add a (mul a (s b 1))) 0)
	))
)

and then

> (add 9 4)
13
> (mul 9 43)
387

Of course this implementation of multiplication will fail for negative inputs of b, but can be fixed as follows

(d mul*
	(q (
		(a b)
		(i (l b 0) (mul (s 0 a) (s 0 b)) (mul a b))
	))
)