This doesn't let you arbitrarily call back into the VM from within
foreign methods. I'm still not sure if that's even a good idea since
God knows what that would mean if you switch fibers while doing that.
But this does allow the very important use case of being able to call
a foreign method from within a call to wrenCall(). In other words,
foreign methods need to always be leaf calls on the call stack, but the
root of that stack can now come from runInterpreter() or wrenCall().
Fix#510.
The VM used to not detect this case. It meant you could get into a
situation where another fiber's caller had completed. Then, when it
tried to resume that fiber, the VM would crash because there was nothing
to resume to.
This is part of thinking through all the cases around re-entrancy. Added
some notes for that too.
There's a lot of changes here and surely some rough edges to iron out.
Also, I need to update the docs. But I want to get closer to landing
this so I can build on it.
This is just for the VM's own internal use, for resolving relative
imports.
Also added a tiny unit test framework for writing tests of low-level
C functionality that isn't exposed directly by the language or VM.
It doesn't actually execute code yet, but it:
- Supports left and right arrow keys for moving the cursor.
- Ctrl-C, Ctrl-D, Ctrl-A, and Ctrl-E for navigating.
- Syntax highlights the line (!).
The next step is to do a rough parse so that we can tell if the line
is an expression, statement, or needs more input. That will tell us
whether we need to interpret it at the top level (statement) and not
worry about a result, evaluate it as an expression and print the result,
or read more lines.
- Add process module with Process class.
- Add "arguments" and "allArguments" methods.
- Docs for same.
- Support passing additional arguments to command line.
- Add "--help" support to command line.
- wrenEnsureSlots()
Lets you go the foreign slot stack to make room for a temporary work
area.
- wrenSetSlotNewList()
Creates a new empty list and stores it in a slot.
- wrenInsertInList()
Takes a value from one slot and inserts it into the list in another.
Still need more functions like getting elements from a list, removing,
etc. but this at least lets you create, populate, and return lists from
foreign methods.
This turns those functions into general-purpose functions for writing
raw C values into slots on the foreign call stack.
Writing a return just means writing a value to slot 0.
I've got some ideas on how to tweak the embedding API, but I want to
see what performance impact they have first, so this adds a little
benchmark that just calls a foreign method a ton of times.
Wren now has three classes of modules:
- The one magic "core" module that's built in and always needed.
- Auxiliary libraries like "meta" and "random". These do not have any
dependencies, so can be used even when you embed Wren inside an
application. But they're also optional and can be disabled if you
don't need them.
- CLI modules. These ones need libuv and are tied to the CLI wrapper
around the VM.
- Add an explicit va_list version. That lets variadic functions
forward to it.
- Fix a GC bug in wrenCall() with return values.
- Make the call API test not re-enter the VM.
- Test that a foreign method can return strings.
- Test that a foreign method can return a string with null bytes.
- Test wrenCall().
- Allow passing NULL for "v" to wrenCall().
- Allow "a" for passing an explicit length byte array to wrenCall().
