This will probably change up again in the future, but this is what we
need for now to make lambdas work.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
We should check this for safety. An error is better than a panic. If we
try to set an unexported field, this would panic. We should prevent
being able to even type unify that though!
This is mainly meant as a useful test case, but might as well have it be
fun too. As an aside, it taught me a surprising result about the %v verb
in printf, and we'll have to decide if it's an issue we care about.
https://github.com/golang/go/issues/46118
The interesting thing about this method is that it uses the simplepoly
API but has no input args-- only the output types are different. If it
had identical types in the input args, that might also have been
interesting, but it's more rare to have none. Hopefully this exercises
our type unification logic.
Map and list types are now unconditionally initialised during an Into()
call to ensure that the only data within them after the operation is
that added by the Into() function.
Prior to this change, map/list types would likely not be cleared prior
to the data being inserted into them with a few exceptions. Nil
pointers or maps/lists that were not sufficient in capacity would be
reinitialised and used to replace the existing backing data store. In
some cases this wouldn't occur meaning any residual data existing in the
container before the Into() call could persist after the data copy
completes. This behaviour is wildly inconsistent and not ideal in the
vast majority of cases. It should be assumed that the Into() call will
preserve nothing and always produce a consistent and deterministic
output.
Signed-off-by: Joe Groocock <me@frebib.net>
Some forms of reflect.Value can cause ValueOf() to panic when there is a
nil pointer somewhere within the reflect.Value, whether that be a
container type like a struct, list or map, or just a raw nil pointer.
In these cases, ValueOf() attempted to dereference the pointer without
ever checking if it was nil. mgmt lang doesn't have pointers of any
kind, so these Golang values cannot be represented in mcl types in the
current form so return a helpful error to the user.
Signed-off-by: Joe Groocock <me@frebib.net>
Into() mutates a given reflect.Value and sets the data represented by
the types.Value into the storage represented by the reflect.Value.
Into() is the opposite to ValueOf() which converts reflect.Value into
types.Value, and in theory they should be (almost) bijective with some
edge case exceptions where the conversion is lossy.
Simply, it replaces reflect.Value.Set() in the broad case, giving finer
control of how the reflect.Value is modified and how the data is set.
types.Value.Value() is now also a redundant function that achieves the
same outcome as Into(), but with less type specificity.
Signed-off-by: Joe Groocock <me@frebib.net>
Replace use of reflect.Value.Len() with NumField() which is intended to
return the number of fields in reflected Struct value.
Len should only be used for Array, Chan, Map, Slice and String types.
Add some trivial sanity check tests for ValueOf() for the simple and
complex container types.
Signed-off-by: Joe Groocock <me@frebib.net>
This adds a giant missing piece of the language: proper function values!
It is lovely to now understand why early programming language designers
didn't implement these, but a joy to now reap the benefits of them. In
adding these, many other changes had to be made to get them to "fit"
correctly. This improved the code and fixed a number of bugs.
Unfortunately this touched many areas of the code, and since I was
learning how to do all of this for the first time, I've squashed most of
my work into a single commit. Some more information:
* This adds over 70 new tests to verify the new functionality.
* Functions, global variables, and classes can all be implemented
natively in mcl and built into core packages.
* A new compiler step called "Ordering" was added. It is called by the
SetScope step, and determines statement ordering and shadowing
precedence formally. It helped remove at least one bug and provided the
additional analysis required to properly capture variables when
implementing function generators and closures.
* The type unification code was improved to handle the new cases.
* Light copying of Node's allowed our function graphs to be more optimal
and share common vertices and edges. For example, if two different
closures capture a variable $x, they'll both use the same copy when
running the function, since the compiler can prove if they're identical.
* Some areas still need improvements, but this is ready for mainstream
testing and use!
This adds the ability to test that functions return the expected
streams, and to model this behaviour over time. This is done via a
"timeline" which runs an ordered list of actions that can both push new
values into the function stream, and wait and expect particular outputs.
Hopefully this will make our function implementations more robust!
It turns out that some planned additions to the parser make it so that
the map type definition can be ambiguous. As a result, this patch
updates the definition so that the map definition is not confused with
an open curly bracket anywhere.
Thanks to pestle and stbenjamin for their help understanding yacc!
This patch adds a simple function API for writing simple, pure
functions. This should reduce the amount of boilerplate required for
most functions, and make growing a stdlib significantly easier. If you
need to build more complex, event-generating functions, or statically
polymorphic functions, then you'll still need to use the normal API for
now.
This also makes all of these pure functions available automatically
within templates. It might make sense to group these functions into
packages to make their logical organization easier, but this is a good
enough start for now.
Lastly, this added some missing pieces to our types library. You can now
use `ValueOf` to convert from a `reflect.Value` to the corresponding
`Value` in our type system, if an equivalent exists.
Unfortunately, we're severely lacking in tests for these new types
library additions, but look forward to growing some in the future!
This is an initial implementation of the mgmt language. It is a
declarative (immutable) functional, reactive, domain specific
programming language. It is intended to be a language that is:
* safe
* powerful
* easy to reason about
With these properties, we hope this language, and the mgmt engine will
allow you to model the real-time systems that you'd like to automate.
This also includes a number of other associated changes. Sorry for the
large size of this patch.
