This change eliminates all traces of the old, legacy errors and warnings.
It also renumbers everything so that we don't have any "gaps". Finally,
it introduces a factory method for new errors and warnings, private to
this package, that ensures we don't accidentally register duplicate IDs.
This change deletes a bunch of old legacy code. I've tagged the
prior changelist as "0.1" in case we need to go back and recover
some of the code (as I expect some of the constraint type logic
and AWS-specific code to come in handy down the road).
🔥🔥🔥
This change adds support for function calls. We do not yet wire it
into the various function call expressions, however, that should be
relatively trivial after this change. (It is dependent on figuring
out the runtime representation of load location objects and subsequent
uses of them). This change also updates the scoping logic to respect
"activation frame" style of lexical scoping, where an inner function
as a result of a call should not have access to the callee context.
This change also includes logic to detect unhandled exceptions and to
print an error as a result. Eventually, we will want stack traces here.
This changes a few things around binding logic, as part of eliminating
all of the legacy logic and weaving it into the new codebase:
* Give Scopes access to the Context object. Related, add a TryRegister
method to Scope that is like RequireRegister, except that instead of
fail-fast upon encountering a duplicate entry, it will issue an error.
* Move all typecheck visitation functions out of the big honkin' switch
and into their own member functions. As this stuff gets more complex,
having everything in one routine was starting to irk my sensibilities.
* Validate that packages have names.
* Store both the package symbol, plus the canonicalized URL used to
resolve it, in the package map. This will help us verify that versions
match for multiple package references resolving to the same symbol.
* Add nice inquiry methods to the Class symbol (Sealed, Abstract, Record,
Interface) that simplify accessing the modifiers on the underlying node.
This change performs typechecking during binding. This is less about
typechecking per se -- since higher level languages will have presumably
given us well-typed IL -- and more about preparing the AST so that we
can evaluate the fully bound nodes to produce a MuGL graph. It also
serves as a "verifier" for the incoming MuIL, however.
This is clearly incomplete, as the dozens of TODOs will make obvious.
But it's a clean checkpoint that does enough interesting typechecking
that I am landing it now.
This change rearranges the old way we dealt with URLs. In the old system,
virtually every reference to an element, including types, was fully qualified
with a possible URL-like reference. (The old pkg/tokens/Ref type.) In the
new model, only dependency references are URL-like. All maps and references
within the MuPack/MuIL format are token and name based, using the new
pkg/tokens/Token and pkg/tokens/Name family of related types.
As such, this change renames Ref to PackageURLString, and RefParts to
PackageURL. (The convenient name is given to the thing with "more" structure,
since we prefer to deal with structured types and not strings.) It moves
out of the pkg/tokens package and into pkg/pack, since it is exclusively
there to support package resolution. Similarly, the Version, VersionSpec,
and related types move out of pkg/tokens and into pkg/pack.
This change cleans up the various binder, package, and workspace logic.
Most of these changes are a natural fallout of this overall restructuring,
although in a few places we remained sloppy about the difference between
Token, Name, and URL. Now the type system supports these distinctions and
forces us to be more methodical about any conversions that take place.
I was sloppy in my use of names versus tokens in the original AST.
Now that we're actually binding things to concrete symbols, etc., we
need to be more precise. In particular, names are just identifiers
that must be "interpreted" in a given lexical context for them to
make any sense; whereas, tokens stand alone and can be resolved without
context other than the set of imported packages, modules, and overall
module structure. As such, names are much simpler than tokens.
As explained in the comments, tokens.Names are simple identifiers:
Name = [A-Za-z_][A-Za-z0-9_]*
and tokens.QNames are fully qualified identifiers delimited by "/":
QName = [ <Name> "/" ]* <Name>
The legal grammar for a token depends on the subset of symbols that
token is meant to represent. However, the most general case, that
accepts all specializations of tokens, is roughly as follows:
Token = <Name> |
<PackageName>
[ ":" <ModuleName>
[ "/" <ModuleMemberName>
[ "." <Class MemberName> ]
]
]
where:
PackageName = <QName>
ModuleName = <QName>
ModuleMemberName = <Name>
ClassMemberName = <Name>
Please refer to the comments in pkg/tokens/tokens.go for more details.
This change further merges the new AST and MuPack/MuIL formats and
abstractions into the core of the compiler. A good amount of the old
code is gone now; I decided against ripping it all out in one fell
swoop so that I can methodically check that we are preserving all
relevant decisions and/or functionality we had in the old model.
The changes are too numerous to outline in this commit message,
however, here are the noteworthy ones:
* Split up the notion of symbols and tokens, resulting in:
- pkg/symbols for true compiler symbols (bound nodes)
- pkg/tokens for name-based tokens, identifiers, constants
* Several packages move underneath pkg/compiler:
- pkg/ast becomes pkg/compiler/ast
- pkg/errors becomes pkg/compiler/errors
- pkg/symbols becomes pkg/compiler/symbols
* pkg/ast/... becomes pkg/compiler/legacy/ast/...
* pkg/pack/ast becomes pkg/compiler/ast.
* pkg/options goes away, merged back into pkg/compiler.
* All binding functionality moves underneath a dedicated
package, pkg/compiler/binder. The legacy.go file contains
cruft that will eventually go away, while the other files
represent a halfway point between new and old, but are
expected to stay roughly in the current shape.
* All parsing functionality is moved underneath a new
pkg/compiler/metadata namespace, and we adopt new terminology
"metadata reading" since real parsing happens in the MetaMu
compilers. Hence, Parser has become metadata.Reader.
* In general phases of the compiler no longer share access to
the actual compiler.Compiler object. Instead, shared state is
moved to the core.Context object underneath pkg/compiler/core.
* Dependency resolution during binding has been rewritten to
the new model, including stashing bound package symbols in the
context object, and detecting import cycles.
* Compiler construction does not take a workspace object. Instead,
creation of a workspace is entirely hidden inside of the compiler's
constructor logic.
* There are three Compile* functions on the Compiler interface, to
support different styles of invoking compilation: Compile() auto-
detects a Mu package, based on the workspace; CompilePath(string)
loads the target as a Mu package and compiles it, regardless of
the workspace settings; and, CompilePackage(*pack.Package) will
compile a pre-loaded package AST, again regardless of workspace.
* Delete the _fe, _sema, and parsetree phases. They are no longer
relevant and the functionality is largely subsumed by the above.
...and so very much more. I'm surprised I ever got this to compile again!
