iota

Iota is a lisp interpreter. It is very much a work in progress.

build:

make

run:

./iota

What it has

• Interpretation.
• Lisp-1 namespacing.
• Lexical binding.
• Common Lisp-style macros.
• Self-evaluating keywords.
• Some arg parsing.
• Some introspection.
• Decent I/O.

What it doesn’t have

• Booleans (nil serves as false)
• Garbage collection.

What I want it to have

• Self-hosted compilation, maybe to some kind of iota bytecode, maybe to javascript, maybe to C, maybe to all three.
• Much more introspection.
• Better arg parsing.
• More (fast) fundamental data structures, like maps/hashtables/dictionaries and resizable vectors.
• Garbage collection.

Acknowledgements

Big chunks of iota were built based on Peter Michaux’s Scheme from Scratch series, which walks through a C implementation of the metacircular scheme intepreter in SICP. Other stuff was built by reading SICP directly. I am also working through Lisp in Small Pieces, so that will probably show up. Still other stuff I just hacked out. Some of it is broken, see below.

Inspiration

• femtolisp
• maru

Broken / TODO

• Quasiquote (backquote) doesn’t nest right backquote should work now
• Variable capture seems to be happening a lot, maybe because quasiquote is broken, or maybe just inherent to common lisp macros in a lisp-1.