`Internal error . . . : bad range code` when evalutaing a simple tetration program

[mobotsar]

The following program is supposed to calculate the tetration of 4 with 4, but instead results in (core dumped). It works correctly for several other inputs including the edge cases.

#!/usr/bin/env janet

(defn pow [a b] (* ;(map (fn [x] a) (range 0 b))))
(defn fold [xs init f] (var acc init) (each x xs (set acc (f x acc))) acc)
(defn tet [a b] (fold (map (fn [x] a) (range 0 b)) 1 pow))
(tet 4 4)

The full error message is

janet internal error at line 458 in file src/core/corelib.c: bad range code
zsh: IOT instruction (core dumped)  janet bug.janet

janet --version prints 1.37.1-local.

Please let me know if there's any more you need me to provide.

[bakpakin]

Adding a trace to range:

(defn xrange [& args] (range ;args))
(trace xrange)
(def range xrange)

I see the following:

trace (xrange 0 4)
trace (xrange 0 1)
trace (xrange 0 4)
trace (xrange 0 256)
trace (xrange 0 1.34078079299426e+154)

So we have ridiculously large bounds for range. Instead of raising an exception, we crash due to some internal logic that tries to allow for floating point steps in range. This should be fixed to just raise an error as we cannot allocate that large of an array. Janet's range is not lazy.

[mobotsar]

Awesome; I figured it was something like that. Thanks!