(The old syntax is still supported as well, for now.)
It is now possible to leave out the parens around if, while, and
do/while conditions, and around alt expressions. Cases in an alt block
can now leave off the case keyword and parens around the pattern.
After the next snapshot, we can start migrating our code to use the
new alt syntax, probably with a pretty-printer pass. The paren-free
syntax will remain optional (you may always parenthesize expressions),
but the old case syntax will no longer be supported in the future.
If a closure inside a case alternative (for example, a for each loop)
referenced a pattern-bound variable, this would cause an assertion
failure in trans. Changed trans::collect_upvars to handle pattern-bound
vars correctly.
Incidentally, eliminated all direct uses of option::get in trans.
Add a failure checkpoint after the typechecking pass. There are still many
fatal errors in typeck, but loosening up this one makes it easier to lean on
the compiler when making changes to types.
Issue #440.
src/comp/syntax is currently just a sub-module of rustc, but it will,
in the near future, be its own crate. This includes:
- The AST data structure
- The parser
- The pretty-printer
- Visit, walk, and fold
- The syntax extension system
- Some utility stuff that should be in the stdlib*
*) Stdlib extensions currently require a snapshot before they can be
used, and the win build is very broken right now. This is temporary
and will be cleaned up when one of those problems goes away.
A lot of code was moved by this patch, mostly towards a more organized
layout. Some package paths did get longer, and I guess the new layout
will take some getting used to. Sorry about that!
Please try not to re-introduce any dependencies in syntax/ on any of
the other src/comp/ subdirs.
This way, the pretty-printer does not have to know about middle::ty.
(This is a preparation for separating the AST functionality into a
separate crate.)
An expression like:
foo(1, fail, 2)
was failing to parse, because the parser was interpreting the comma
as the start of an expression that was an argument to fail, rather
than recognizing that the fail here has no arguments
Fixed this by using can_begin_expr to determine whether the next
token after a fail token suggests that this is a nullary fail or a
unary fail.
In addition, when translating calls, check before translating each
argument that the block still isn't terminated. This has the effect
that if an argument list includes fail, the back-end won't keep trying
to generate code for successive arguments and trip the !*terminated
assertion.
The code for translating a fail (for example) would call
Unreachable(), which terminates the block; if a fail appeared as an
argument, this would cause an LLVM assertion failure. Changed
trans_call to handle this situation correctly.
If the channel is associated with a port then the destructor will assert.
Additionally, destruction of the object is not always appropriate. This brings
the deref() method into sync with the behavior of generated rust code which
only invokes destroy() once the reference count goes to 0.
The macro with the extra dtor parameter is intended for structures like
rust_chan which may not necessarily delete themselves when the ref count
becomes 0. This functionality will be used in an upcoming changeset.
Only link attributes of the meta_list type are considered when matching crate
attributes. Instead of doing nothing we can at least log that link attributes
of other types were ignored.
(Using the * operator.)
This makes tags more useful as nominal 'newtype' types, since you no
longer have to copy out their contents (or construct a cumbersome
boilerplate alt) to access them.
I could have gone with a scheme where you could dereference individual
arguments of an n-ary variant with ._0, ._1, etc, but opted not to,
since we plan to move to a system where all variants are unary (or, I
guess, nullary).
This is a preparation for tags-as-nominal-types. A tag that has only a
single variant is now represented, at run-time, as simply a tuple of
the variant's parameters, with the variant id left off.
This is important since we are going to be making functions noncopyable
soon, which means we'll be seeing a lot of boxed functions.
(*f)(...) is really just too heavyweight.
Doing the autodereferencing was a very little bit tricky since
trans_call works with an *lval* of the function whereas existing
autoderef code was not for lvals.
