It assumed node_ids increased monotonically for locals, but macros
make this no longer the case, and it was a dubious assumption anyway.
It now numbers locals itself and uses that to determine which precede
which.
The syntax is
alt x {
mypat where mycond { ... }
}
The condition may refer to any of the variables bound by the pattern.
When a guard fails, pattern-matching continues with the next pattern.
Closes#857
This actually basically makes things worse, since we get less nice
type system guarentees but it will make doing type inferred blocks a
fair deal less painful. I'm not /really/ happy about this...
You can now say
let {bcx, val} = some_result_returner();
Similar for loop variables. Assigning to such variables is not safe
yet. Function arguments also remain a TODO.
This adds parser support and most of the machinery for
auto x = 10, y = 20;
However, the above still goes wrong somewhere in typestate, causing
the state checker to believe only the last variable in the list is
initialized after the statement.
Tim, if you have a moment, could you go over the changes to the tstate
code in this patch and see where I'm going wrong?
Multi-var-decls without the typestate extension
Add a loop
Programs with constrained types now parse and typecheck, but
typestate doesn't check them specially, so the one relevant test
case so far is XFAILed.
Also rewrote all of the constraint-related data structures in the
process (again), for some reason. I got rid of a superfluous
data structure in the context that was mapping front-end constraints
to resolved constraints, instead handling constraints in the same
way in which everything else gets resolved.
You can now say
expr_move(?dst, ?src) | expr_assign(?dst, ?src) { ... }
to match both expr_move and expr_assign. The names, types, and number
of bound names have to match in all the patterns.
Closes#449.
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.
