`getValue` -> `value`
`getValueOr` -> `value_or`
`hasValue` -> `has_value`
`map` -> `transform`
The old API will be deprecated in the rebranch.
To avoid merge conflicts, use the new API already in the main branch.
rdar://102362022
In the Swift grammar, the top-level of a source file is a mix of three
different kinds of "items": declarations, statements, and expressions.
However, the existing parser forces all of these into declarations at
parse time, wrapping statements and expressions in TopLevelCodeDecls,
so the primary API for getting the top-level entities in source files
is based on getting declarations.
Start generalizing the representation by storing ASTNode instances at
the top level, rather than declaration pointers, updating many (but
not all!) uses of this API. The walk over declarations is a (cached)
filter to pick out all of the declarations. Existing parsed files are
unaffected (the parser still creates top-level code declarations), but
the new "macro expansion" source file kind skips creating top-level
code declarations so we get the pure parse tree. Additionally, some
generalized clients (like ASTScope lookup) will now look at the list
of items, so they'll be able to walk into statements and expressions
without the intervening TopLevelCodeDecl.
Over time, I'd like to phase out `getTopLevelDecls()` entirely,
relying on the new `getTopLevelItems()` for parsed content. We can
introduce TopLevelCodeDecls more lazily for semantic walks.
Introduce a new source file kind to describe source files for macro
expansions, and include the macro expression that they expand. This
establishes a "parent" relationship
Also track every kind of auxiliary source file---whether for macro
expansions or other reasons---that is introduced into a module, adding
an operation that allows us to find the source file that contains a
given source location.
Allow user-defined macros to be loaded from dynamic libraries and evaluated.
- Introduce a _CompilerPluginSupport module installed into the toolchain. Its `_CompilerPlugin` protocol acts as a stable interface between the compiler and user-defined macros.
- Introduce a `-load-plugin-library <path>` attribute which allows users to specify dynamic libraries to be loaded into the compiler.
A macro library must declare a public top-level computed property `public var allMacros: [Any.Type]` and be compiled to a dynamic library. The compiler will call the getter of this property to obtain and register all macros.
Known issues:
- We current do not have a way to strip out unnecessary symbols from the plugin dylib, i.e. produce a plugin library that does not contain SwiftSyntax symbols that will collide with the compiler itself.
- `MacroExpansionExpr`'s type is hard-coded as `(Int, String)`. It should instead be specified by the macro via protocol requirements such as `signature` and `genericSignature`. We need more protocol requirements in `_CompilerPlugin` to handle this.
- `dlopen` is not secure and is only for prototyping use here.
Friend PR: apple/swift-syntax#1022
Introduce an experimental option `BuiltinMacros` that takes the magic
literals (`#file`, `#line`, `#function`, etc.) after type checking and
processes the original source for the expression using the build
syntactic macro system in the swift-syntax library. At present, the
result of expansion is printed to standard output, but it's enough to
verify that we're able to find the corresponding syntax node based on
the C++ AST.
Rework the ASTGen interface to split apart parsing a source file,
turning the top-level declarations from that source file into C++ AST
nodes, and then deallocating that source file. Hold on to the source
file in the C++ SourceFile abstraction so we can query it later if we
need to.
And we will need to.
Introduce `MacroExpansionExpr` and `MacroExpansionDecl` and plumb it through. Parse them in roughly the same way we parse `ObjectLiteralExpr`.
The syntax is gated under `-enable-experimental-feature Macros`.
When the experimental flag `ParserASTGen` is enabled, the compiler has
ASTGen built, we're not performing code completion, and we're not
parsing SIL... go through the new parser and ASTGen to build the
abstract syntax tree.
Only introduce it and its dependency when the new Swift parser is being
built, and rely more on existing logic to make sure we get the right
build/link flags.
Fixes rdar://100872195 ( error: 'move' can only be applied to lvalues
error: Can not use feature when experimental move only is disabled!)
Identifiers with a single underscore are not reserved for use by the
language implementation. It is perfectly valid for a library to define
its own '_move'.
The contextual _move keyword should only be parse when it is followed by an lvalue, so should *not* conflict with user-defined '_move' functions.
https://github.com/apple/swift-evolution/blob/main/proposals/0366-move-function.md#source-compatibility
