Using a bitset to indicate which stack values are upvalues, we
can more accurately track when a reference to a stack value
persists after the stack frame exits.
This way we can support fewer build configurations. Also, remove
all undefined behavior due to use of memcpy with NULL pointers. GCC
was exploiting this to remove NULL checks in some builds.
This means we can add new properties to abstract types without
breaking old code. We can also make simple abstract types without
needing to add many NULL fields to the type.
This changes the implementation of the `next` function which
is now used to implement each. This let's us iterate over
more types, not just tables and structs.
In some cases, one might want to disable what is currently
SipHash for speed / better security mechansims. For example, using
red black trees for caches rather than hash tables.
The hash key still needs to randomly initialized
for the security advantage, but this patch is a
step closer to avoiding hash based DOS.
Further work may including exposing the raw hash
function for use by abstract types who also choose to
implement hash.
If JANET_ENTRY_NAME is defined, we are compiling into a single binary.
In this case, we don't want to define the config symbol multiple times
with same name, as this causes the linker error.
While C functions are not re-entrant, signaling from a C function
can be used to implement async returns. When resuming a fiber that
signalled from within a C function, the fiber is started after the
instruction that emitted the signal. The resume argument is used
as the return result from the c function.
This unifies equality and comparison checking. Before, we had
separate functions and vm opcodes for comparing general values vs.
for comparing numbers, where the numberic functions were polymorphic and
had special cases for handling NaNs. By unfiying them, abstract types
can now better integrate with other number types and behave as keys.
For now, the old functions are aliased but will eventually be removed.
Gives more control over unmarshalling
abstract types. This should also
make it possible/easy to write abstract types that cannot
cause unmarshal to segfault.
This makes the names of the opcodes match their implied functionality.
We also rename the C functions to match the opcodes and source level
functionality.
Rather than messing with janet_core_dictionary, we
instead cache the core enevironment, and pull out the
needed tables from there. This is more flexible, more correct, and
also exposes janet_resolve_core, which can be easily used from the C
API.
