HISTORY.org

Release Notes for klvm

v0.2

Add support for “cons-based” eval.

Before v0.2, when evaluating a list (op arg1 arg2 ...), the op operator had to be an atom. As of v0.2, it can now be a list. Note that in this case, the arguments arg1 arg2 ... are ignored.

Briefly, ((c SEXP ARGS)) is equivalent to (e SEXP ARGS). The e operator is deprecated, and you should stop using it, and start using the new form instead. In v0.3, the e operator will be removed.

To make this easier, if the environment variable KLVM_DISALLOW_E_OP is set, whenever a use of the e operator is encountered, an exception will be raised

If KLVM_DISALLOW_E_OP is set to the special value breakpoint, the python debugger will be launched via breakpoint(), newly introduced in Python 3.7.

Example

$ brun '(e (q (+ (q 500))) (q ()))'
500

$ KLVM_DISALLOW_E_OP=1 brun '(e (q (+ (q 500))) (q ()))'
FAIL: e operator no longer supported (e (q (+ (q 500))) (q ()))

$ KLVM_DISALLOW_E_OP=breakpoint brun '(e (q (+ (q 500))) (q ()))'
(e (q (+ (q 500))) (q ()))
> /Users/kiss/projects/chik/klvm/make_eval.py(46)eval_core()
-> raise EvalError("e operator no longer supported", form)

$ KLVM_DISALLOW_E_OP=breakpoint brun '((c (q (+ (q 500))) (q ())))'
500

For more information on environment variables, take a look at this article (or hit the internet).

Remove custom “null” type.

In v0.1, the () null value was represented by a unique atom that was different from every other atom. In v0.2 and beyond, the () value is represented by an empty binary string, and so has the same representation as 0. This also affects i, which now views 0 as false.

Example

v0.1

$ brun '(q 0)'
0
$ brun '(q ())'
()
$ brun '(i (q ()) (q 500) (q 600))'
600
$ brun '(i (q 0) (q 500) (q 600))'
500
$ brun '(i (q 1) (q 500) (q 600))'
500

v0.2

$ brun '(q 0)'
()
$ brun '(q ())'
()
$ brun '(i (q ()) (q 500) (q 600))'
600
$ brun '(i (q 0) (q 500) (q 600))'
600
$ brun '(i (q 1) (q 500) (q 600))'
500

v0.1

Initial release.