I forgot to include these two invariants which are occasionally
necessary, although in most cases they're necessary to prevent incorrect
code from getting past unification. In any case, they would have been
caught by the engine.
These weren't yet exposed in mcl. They're now available under the same
Meta namespace as the normal meta param structs. Even though they live
as a separate trait, they should be exposed together for a consistent
interface in mcl. If autoedge or autogroup ever grow additional params,
we can always add: `Meta:autoedge:something` to break it down further.
This adds a core looping construct by allowing a list of names to build
a resource. They'll all have the same parameters, but they'll
intelligently add the correct list of edges that they'd individually
create.
Constructs like these are one reason we do NOT have actual looping
functionality in the language, and it should stay that way.
Instead of adding complexity to the unification engine, we can add a
fake placeholder expression that is unreachable by the AST, but used for
unification so that we can ensure a "wrap" invariant has some contents.
Ideally we'd improve the unification engine, but we'll leave that for
the future, and it's easy to revert this one commit in the future.
This signals to an interested consumer that two or more compatible
resources can be merged safely. This is so that we can avoid the
"duplicate resource" design problem that puppet had.
To test this, you can run:
./mgmt run --tmp-prefix lang --lang 'pkg "cowsay" { state => "installed", } pkg "cowsay" { state => "newest", }'
which should work.
These two cases should be allowed in our language. This is something
that puppet got wrong, and hopefully this makes writing modules more
sane in mcl, since two modules both depending on a "cowsay" package
won't cause compile errors.
This only checks the language. The de-duplication is done there. We
don't currently have a check for this in the engine. (We should!)
This enables imports in mcl code, and is one of last remaining blockers
to using mgmt. Now we can start writing standalone modules, and adding
standard library functions as needed. There's still lots to do, but this
was a big missing piece. It was much harder to get right than I had
expected, but I think it's solid!
This unfortunately large commit is the result of some wild hacking I've
been doing for the past little while. It's the result of a rebase that
broke many "wip" commits that tracked my private progress, into
something that's not gratuitously messy for our git logs. Since this was
a learning and discovery process for me, I've "erased" the confusing git
history that wouldn't have helped. I'm happy to discuss the dead-ends,
and a small portion of that code was even left in for possible future
use.
This patch includes:
* A change to the cli interface:
You now specify the front-end explicitly, instead of leaving it up to
the front-end to decide when to "activate". For example, instead of:
mgmt run --lang code.mcl
we now do:
mgmt run lang --lang code.mcl
We might rename the --lang flag in the future to avoid the awkward word
repetition. Suggestions welcome, but I'm considering "input". One
side-effect of this change, is that flags which are "engine" specific
now must be specified with "run" before the front-end name. Eg:
mgmt run --tmp-prefix lang --lang code.mcl
instead of putting --tmp-prefix at the end. We also changed the GAPI
slightly, but I've patched all code that used it. This also makes things
consistent with the "deploy" command.
* The deploys are more robust and let you deploy after a run
This has been vastly improved and let's mgmt really run as a smart
engine that can handle different workloads. If you don't want to deploy
when you've started with `run` or if one comes in, you can use the
--no-watch-deploy option to block new deploys.
* The import statement exists and works!
We now have a working `import` statement. Read the docs, and try it out.
I think it's quite elegant how it fits in with `SetScope`. Have a look.
As a result, we now have some built-in functions available in modules.
This also adds the metadata.yaml entry-point for all modules. Have a
look at the examples or the tests. The bulk of the patch is to support
this.
* Improved lang input parsing code:
I re-wrote the parsing that determined what ran when we passed different
things to --lang. Deciding between running an mcl file or raw code is
now handled in a more intelligent, and re-usable way. See the inputs.go
file if you want to have a look. One casualty is that you can't stream
code from stdin *directly* to the front-end, it's encapsulated into a
deploy first. You can still use stdin though! I doubt anyone will notice
this change.
* The scope was extended to include functions and classes:
Go forth and import lovely code. All these exist in scopes now, and can
be re-used!
* Function calls actually use the scope now. Glad I got this sorted out.
* There is import cycle detection for modules!
Yes, this is another dag. I think that's #4. I guess they're useful.
* A ton of tests and new test infra was added!
This should make it much easier to add new tests that run mcl code. Have
a look at TestAstFunc1 to see how to add more of these.
As usual, I'll try to keep these commits smaller in the future!
This adds a new method to the *StmtProg that lets us determine if the
prog contains only what is necessary for a scope and nothing more. This
is useful because that is exactly what is produced when doing an import.
With this detection method, we can know if a module contains dead code
that might mislead the user into thinking it will get run when it won't.
This is meant to be useful for the downloader. This will probably get
more complicated over time, but for now the goal is to have it simple
enough to work for 80% of use cases.
This should prepare us so that we can build native mcl code alongside
the core *.go files which we already have. This includes a single mcl
file that is used as a placeholder so that the build doesn't fail if we
don't have any mcl files in the core/ directory. It will get ignored
automatically.
This is a giant refactor to move functions into a hierarchial module
layout. While this isn't entirely implemented yet, it should work
correctly once all the import bits have landed. What's broken at the
moment is the template function, which currently doesn't understand the
period separator.
This allows matching underscores in some of the identifier's, but not
when they're the last character.
This caused me to suffer a bit of pain tracking down a bug which turned
out to be in the lexer. It started with a failing test that I wrote in:
974c2498c4
and which followed with a fix in:
52682f463a
Glad that's fixed!
This adds parsing of the upcoming "import" statement contents. It is the
logic which determines how an import statement is read in the language.
Hopefully it won't need any changes or additional magic additions.
This adds a LexParseWithOffsets method that also takes a list of offsets
to be used if our input stream is composed of multiple io.Readers
combined together.
At the moment the offsets are based on line count instead of file size.
I think the latter would be preferable, but it seems it's much more
difficult to implement as it probably requires support in the lexer and
parser. That improved solution would probably be faster, and more
correct in case someone passed in a file without a trailing newline.
This adds support for dotted identifiers in include statements, var
expressions and function call expressions. The dotted identifiers are
used to refer to classes, bind statements, and function definitions
(respectively) that are included in the scope by import statements.
This adds a new interface Node which must implement the Apply method.
This method traverse the entire AST and applies a function to each node.
Both Stmt and Expr must implement this.
This expands the Stmt and Expr interfaces to add an Init method. This
is used to pass in Debug and Logf values, but is also used to validate
the AST. This gets rid of standalone use of the "log" package.
This requires breaking changes in gofmt. It is hilarious that this was
changed. Oh well. This also moves to the latest stable etcd. Lastly,
this changes the `go vet` testing to test by package, since the new go
vet changed how it works and now fails without this change.
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 adds the additional bits onto the class/include statements to
support or detect class recursion. It's not currently supported, but
I figured I'd commit the detection code as a variant of the recursion
implementation, since I think this is correct, and it was a bit tricky
for me to get it right.
This adds support for the class definition statement and the include
statement which produces the output from the corresponding class.
The classes in this language support optional input parameters.
In contrast with other tools, the class is *not* a singleton, although
it can be used as one. Using include with equivalent input parameters
will cause the class to act as a singleton, although it can also be used
to produce distinct output.
The output produced by including a class is actually a list of
statements (a prog) which is ultimately a list of resources and edges.
This is different from functions which produces values.
This means that it's legal to produce two compatible (usually identical)
resources without a compile error and without causing two of them to get
run. It's too bad puppet never got this right.
It's probably worth checking if this could be done for edges too, and if
the logic can be contained in the engine and not in the frontend.
