The new RNG wraps up state for random number generation, so
one can have many rngs and even marshal and unmarshal them.
Adds math/rng, math/rng-uniform, and math/rng-int.
Also introduce `in` and change semantics for
indexing out of range. This commit enforces stricter
invariants on keys when indexing via a function call
on the data structure, or the new `in` function.
The `get` function is now more lax about keys, and will
not throw an error when a bad key is used for a data structure, instead
returning the default value.
This helps for temporarily setting vars in a safe
manner that is guaranteed not to leave vars in a bad state
(assuming that a fiber does not emit debug or use signal and
is never resumed).
The print family of functions now writes output
to an optional buffer instead of a file bound to :out.
This means output can be more easily captured an redirected.
This should be friendlier to most users. It does, however, mean
we lose range information. However, range information could be
recovered by re-parsing, as janet's grammar is simple enough to do this.
This allows better stacktraces when manually intercepting
signals to clean up resources. Also allows functionality
from Common Lisp's unwind-protect, such as calling cleanup code
while unwindinding the stack, restarting on certain signals, and
just in general having more control over signal and signal propagation.
Also fix a bug encountered while implementing with-resource in the
compiler. Desturcturing arguments that were not the last argument
would often result in bad code generation, as slots used to destructure
the earlier arguments would invalidate the later parameters. This is
fixed by allocating all named parameters before doing any destructuring.
