This adds a for statement which is used to iterate over a list with a
body of statements. This is an important data transformation tool which
should be used sparingly, but is important to have.
An import statement inside of a for loop is not currently supported. We
have a simple hack to detect the obvious cases, but more deeply nested
scenarios probably won't be caught, and you'll get an obscure error
message if you try to do this.
This was incredibly challenging to get right, and it's all thanks to Sam
for his brilliance.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
This adds an initial implementation of printing line numbers on type
unification errors. It also attempts to print a visual position
indicator for most scenarios.
This patch was started by Felix Frank and finished by James Shubin.
Co-authored-by: Felix Frank <Felix.Frank.de@gmail.com>
Instead of constantly making these updates, let's just remove the year
since things are stored in git anyways, and this is not an actual modern
legal risk anymore.
This adds a modern type unification algorithm, which drastically
improves performance, particularly for bigger programs.
This required a change to the AST to add TypeCheck methods (for Stmt)
and Infer/Check methods (for Expr). This also changed how the functions
express their invariants, and as a result this was changed as well.
This greatly improves the way we express these invariants, and as a
result it makes adding new polymorphic functions significantly easier.
This also makes error output for the user a lot better in pretty much
all scenarios.
The one downside of this patch is that a good chunk of it is merged in
this giant single commit since it was hard to do it step-wise. That's
not the end of the world.
This couldn't be done without the guidance of Sam who helped me in
explaining, debugging, and writing all the sneaky algorithmic parts and
much more. Thanks again Sam!
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
With the recent merging of embedded package imports and the entry CLI
package, it is now possible for users to build in mcl code into a single
binary. This additional permission makes it explicitly clear that this
is permitted to make it easier for those users. The condition is phrased
so that the terms can be "patched" by the original author if it's
necessary for the project. For example, if the name of the language
(mcl) changes, has a differently named new version, someone finds a
phrasing improvement or a legal loophole, or for some other
reasonable circumstance. Now go write some beautiful embedded tools!
This implements a new type of syntactic sugar for the common pattern of
a base class which returns a child class, and so on. Instead of needing
to repeatedly indent the child classes, we can instead prefix them at
the definition site (where created with the class keyword) with the name
of the parent class, followed by a colon, to get the desired embedded
sugar.
For example, instead of writing:
class base() {
class inner() {
class deepest() {
}
}
}
You can instead write:
class base() {
}
class base:inner() {
}
class base:inner:deepest() {
}
Of course, you can only access any of the inner classes by first
including (with the include keyword) a parent class, and then
subsequently including the inner one.
This adds support for `include as <identifier>` type statements which in
addition to pulling in any defined resources, it also makes the contents
of the scope of the class available to the scope of the include
statement, but prefixed by the identifier specified.
This makes passing data between scopes much more powerful, and it also
allows classes to return useful classes for subsequent use.
This also improves the SetScope procedure and adds to the Ordering
stage. It's unclear if the current Ordering stage can handle all code,
or if there exist corner-cases which are valid code, but which would
produce a wrong or imprecise topological sort.
Some extraneous scoping bugs still exist, which expose certain variables
that we should not depend on in future code.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
This is a newer implementation of the panic magic. I kept the old commit
in for posterity and to show the difference. The two versions are
identical to the end-user with one exception: the newer version doesn't
include a useless panic resource in the graph when there is no panic. In
this version, the panic function returns false and the if statement it's
the condition of, doesn't produce the resource within. On error, we
still consume the function in the if expression, and doing so causes
everything to shutdown.
The other benefit is that the implementation is much cleaner and doesn't
need the interpolate hack.
It's valuable to check your runtime values and to shut down the entire
engine in case something doesn't match. This patch adds some magic
plumbing to support a "panic" mechanism.
A new "panic" statement gets transparently converted into a panic
function and panic resource. The former errors if the input is not
empty. The latter must be present to consume the value, but doesn't
actually do anything.
This seems to make things work. I'm worried I might have an ordering bug
where we might choose the wrong precedence if we write ambiguous code
somehow, but at least for now, let's commit this and move on. Hopefully
the nonassoc stuff is actually correct.
Instead of in the lexer. I think this simplifies things and gives the
parser more information which should hopefully make it easier to parse
without shift/reduce conflicts.
It's a normally named function for now, until we think of a common
package to move it into.
Hopefully this makes improving the lexer and parser easier for now. We
can consider bringing it back if needed.
There were a bunch of packages that weren't well documented. With the
recent split up of the lang package, I figured it would be more helpful
for new contributors who want to learn the structure of the project.
This is a giant refactor to split the giant lang package into many
subpackages. The most difficult piece was figuring out how to extract
the extra ast structs into their own package, because they needed to
call two functions which also needed to import the ast.
The solution was to separate out those functions into their own
packages, and to pass them into the ast at the root when they're needed,
and to let the relevant ast portions call a handle.
This isn't terribly ugly because we already had a giant data struct
woven through the ast.
The bad part is rebasing any WIP work on top of this.
