They are still are not completely correct, since it does not handle
graphemes at all, just codepoints, but at least it handles the common
case correctly.
The calculation was previously very wrong (rather than just a little bit
wrong): it wasn't accounting for the fact that every character is 1
byte, and so multibyte characters were pretending to be zero width.
cc #8706
file.
Previously multibyte UTF-8 chars were being recorded as byte offsets
from the start of the file, and then later compared against global byte
positions, resulting in the compiler possibly thinking it had a byte
position pointing inside a multibyte character, if there were multibyte
characters in any non-crate files. (Although, sometimes the byte offsets
line up just right to not ICE, but that was a coincidence.)
Fixes#11136.
Fixes#11178.
This commit removes deriving(ToStr) in favor of deriving(Show), migrating all impls of ToStr to fmt::Show.
Most of the details can be found in the first commit message.
Closes#12477
This commit changes the ToStr trait to:
impl<T: fmt::Show> ToStr for T {
fn to_str(&self) -> ~str { format!("{}", *self) }
}
The ToStr trait has been on the chopping block for quite awhile now, and this is
the final nail in its coffin. The trait and the corresponding method are not
being removed as part of this commit, but rather any implementations of the
`ToStr` trait are being forbidden because of the generic impl. The new way to
get the `to_str()` method to work is to implement `fmt::Show`.
Formatting into a `&mut Writer` (as `format!` does) is much more efficient than
`ToStr` when building up large strings. The `ToStr` trait forces many
intermediate allocations to be made while the `fmt::Show` trait allows
incremental buildup in the same heap allocated buffer. Additionally, the
`fmt::Show` trait is much more extensible in terms of interoperation with other
`Writer` instances and in more situations. By design the `ToStr` trait requires
at least one allocation whereas the `fmt::Show` trait does not require any
allocations.
Closes#8242Closes#9806
Makes labelled loops hygiene by performing renaming of the labels defined in e.g. `'x: loop { ... }` and then used in break and continue statements within loop body so that they act hygienically when used with macros.
Closes#12262.
Makes labelled loops hygiene by performing renaming of the labels
defined in e.g. `'x: loop { ... }` and then used in break and continue
statements within loop body so that they act hygienically when used with
macros.
Closes#12262.
These two containers are indeed collections, so their place is in
libcollections, not in libstd. There will always be a hash map as part of the
standard distribution of Rust, but by moving it out of the standard library it
makes libstd that much more portable to more platforms and environments.
This conveniently also removes the stuttering of 'std::hashmap::HashMap',
although 'collections::HashMap' is only one character shorter.
This PR merges `IterBytes` and `Hash` into a trait that allows for generic non-stream-based hashing. It makes use of @eddyb's default type parameter support in order to have a similar usage to the old `Hash` framework.
Fixes#8038.
Todo:
- [x] Better documentation
- [ ] Benchmark
- [ ] Parameterize `HashMap` on a `Hasher`.
Closes#12366.
Parentheses around assignment statements such as
let mut a = (0);
a = (1);
a += (2);
are not necessary and therefore an unnecessary_parens warning is raised when
statements like this occur.
The warning mechanism was refactored along the way to allow for code reuse
between the routines for checking expressions and statements.
Code had to be adopted throughout the compiler and standard libraries to comply
with this modification of the lint.
This patch merges IterBytes and Hash traits, which clears up the
confusion of using `#[deriving(IterBytes)]` to support hashing.
Instead, it now is much easier to use the new `#[deriving(Hash)]`
for making a type hashable with a stream hash.
Furthermore, it supports custom non-stream-based hashers, such as
if a value's hash was cached in a database.
This does not yet replace the old IterBytes-hash with this new
version.
This is in preparation to remove the implementations of ToStrRadix in integers, and to remove the associated logic from `std::num::strconv`.
The parts that still need to be liberated are:
- `std::fmt::Formatter::runplural`
- `num::{bigint, complex, rational}`
This "bubble up an error" macro was originally named if_ok! in order to get it
landed, but after the fact it was discovered that this name is not exactly
desirable.
The name `if_ok!` isn't immediately clear that is has much to do with error
handling, and it doesn't look fantastic in all contexts (if if_ok!(...) {}). In
general, the agreed opinion about `if_ok!` is that is came in as subpar.
The name `try!` is more invocative of error handling, it's shorter by 2 letters,
and it looks fitting in almost all circumstances. One concern about the word
`try!` is that it's too invocative of exceptions, but the belief is that this
will be overcome with documentation and examples.
Close#12037
Currently, the format_args! macro and its downstream macros in turn
expand to series of let statements, one for each of its arguments, and
then the invocation of the macro function. If one or more of the
arguments are RefCell's, the enclosing statement for the temporary of
the let is the let itself, which leads to scope problem. This patch
changes let's to a match expression.
Closes#12239.
Currently, the format_args! macro and its downstream macros in turn
expand to series of let statements, one for each of its arguments, and
then the invocation of the macro function. If one or more of the
arguments are RefCell's, the enclosing statement for the temporary of
the let is the let itself, which leads to scope problem. This patch
changes let's to a match expression.
Closes#12239.
Closes#11692. Instead of returning the original expression, a dummy expression
(with identical span) is returned. This prevents infinite loops of failed
expansions as well as odd double error messages in certain situations.
Now that fold_item can return multiple items, this is pretty trivial. It
also recursively expands generated items so ItemDecorators can generate
items that are tagged with ItemDecorators!
Closes#4913
The old method of building up a list of items and threading it through
all of the decorators was unwieldy and not really scalable as
non-deriving ItemDecorators become possible. The API is now that the
decorator gets an immutable reference to the item it's attached to, and
a callback that it can pass new items to. If we want to add syntax
extensions that can modify the item they're attached to, we can add that
later, but I think it'll have to be separate from ItemDecorator to avoid
strange ordering issues.
@huonw
The old method of building up a list of items and threading it through
all of the decorators was unwieldy and not really scalable as
non-deriving ItemDecorators become possible. The API is now that the
decorator gets an immutable reference to the item it's attached to, and
a callback that it can pass new items to. If we want to add syntax
extensions that can modify the item they're attached to, we can add that
later, but I think it'll have to be separate from ItemDecorator to avoid
strange ordering issues.
The first setp for #9880 is to add a new `crate` keyword. This PR does exactly that. I took a chance to refactor `parse_item_foreign_mod` and I broke it down into 2 separate methods to isolate each feature.
The next step will be to push a new stage0 snapshot and then get rid of all `extern mod` around the code.
Externally loaded libraries are able to do things that cause references
to them to survive past the expansion phase (e.g. creating @-box cycles,
launching a task or storing something in task local data). As such, the
library has to stay loaded for the lifetime of the process.
This patch gets rid of ObsoleteExternModAttributesInParens and
ObsoleteNamedExternModule since the replacement of `extern mod` with
`extern crate` avoids those cases and raises different errors. Both have
been around for at least a version which makes this a good moment to get
rid of them.
This patch adds a new keyword `crate` which is intended to replace mod
in the context of `extern mod` as part of the issue #9880. The patch
doesn't replace all `extern mod` cases since it is necessary to first
push a new snapshot 0.
The implementation could've been less invasive than this. However I
preferred to take this chance to split the `parse_item_foreign_mod`
method and pull the `extern crate` part out of there, hence the new
method `parse_item_foreign_crate`.
This patch replaces all `crate` usage with `krate` before introducing the
new keyword. This ensures that after introducing the keyword, there
won't be any compilation errors.
krate might not be the most expressive substitution for crate but it's a
very close abbreviation for it. `module` was already used in several
places already.
This resolves issue #12157. Does that do it already or is there something else that needs taking care of?
As a side note, there seems to be some documentation, in which the old existence of the do keyword is explained. The list of keywords is not up-to-date either. But these are certainly separate issues.
Resolves issue #12157. `do` is hereby reinstated as a keyword; no syntax is
associated with it though. Along the way, a unit test had to be adapted, since
it was using `do` as a method identifier.
Breaking changes:
- Any code using `do` as an identifier will no longer work.
Repair a rather embarassingly obvious hole that I created as part of #9629. In particular, prevent `&mut` borrows of data in an aliasable location. This used to be prevented through the restrictions mechanism, but in #9629 I modified those rules incorrectly.
r? @pcwalton
Fixes#11913
fourcc!() allows you to embed FourCC (or OSType) values that are
evaluated as u32 literals. It takes a 4-byte ASCII string and produces
the u32 resulting in interpreting those 4 bytes as a u32, using either
the platform-native endianness, or explicitly as big or little endian.
Error messages cleaned in librustc/middle
Error messages cleaned in libsyntax
Error messages cleaned in libsyntax more agressively
Error messages cleaned in librustc more aggressively
Fixed affected tests
Fixed other failing tests
Last failing tests fixed
The lexer and json were using `transmute(-1): char` as a sentinel value for EOF, which is invalid since `char` is strictly a unicode codepoint.
Fixing this allows for range asserts on chars since they always lie between 0 and 0x10FFFF.
The transmute was unsound.
There are many instances of .unwrap_or('\x00') for "ignoring" EOF which
either do not make the situation worse than it was (well, actually make
it better, since it's easy to grep for places that don't handle EOF) or
can never ever be read.
Fixes#8971.
This has been a long time coming. Conditions in rust were initially envisioned
as being a good alternative to error code return pattern. The idea is that all
errors are fatal-by-default, and you can opt-in to handling the error by
registering an error handler.
While sounding nice, conditions ended up having some unforseen shortcomings:
* Actually handling an error has some very awkward syntax:
let mut result = None;
let mut answer = None;
io::io_error::cond.trap(|e| { result = Some(e) }).inside(|| {
answer = Some(some_io_operation());
});
match result {
Some(err) => { /* hit an I/O error */ }
None => {
let answer = answer.unwrap();
/* deal with the result of I/O */
}
}
This pattern can certainly use functions like io::result, but at its core
actually handling conditions is fairly difficult
* The "zero value" of a function is often confusing. One of the main ideas
behind using conditions was to change the signature of I/O functions. Instead
of read_be_u32() returning a result, it returned a u32. Errors were notified
via a condition, and if you caught the condition you understood that the "zero
value" returned is actually a garbage value. These zero values are often
difficult to understand, however.
One case of this is the read_bytes() function. The function takes an integer
length of the amount of bytes to read, and returns an array of that size. The
array may actually be shorter, however, if an error occurred.
Another case is fs::stat(). The theoretical "zero value" is a blank stat
struct, but it's a little awkward to create and return a zero'd out stat
struct on a call to stat().
In general, the return value of functions that can raise error are much more
natural when using a Result as opposed to an always-usable zero-value.
* Conditions impose a necessary runtime requirement on *all* I/O. In theory I/O
is as simple as calling read() and write(), but using conditions imposed the
restriction that a rust local task was required if you wanted to catch errors
with I/O. While certainly an surmountable difficulty, this was always a bit of
a thorn in the side of conditions.
* Functions raising conditions are not always clear that they are raising
conditions. This suffers a similar problem to exceptions where you don't
actually know whether a function raises a condition or not. The documentation
likely explains, but if someone retroactively adds a condition to a function
there's nothing forcing upstream users to acknowledge a new point of task
failure.
* Libaries using I/O are not guaranteed to correctly raise on conditions when an
error occurs. In developing various I/O libraries, it's much easier to just
return `None` from a read rather than raising an error. The silent contract of
"don't raise on EOF" was a little difficult to understand and threw a wrench
into the answer of the question "when do I raise a condition?"
Many of these difficulties can be overcome through documentation, examples, and
general practice. In the end, all of these difficulties added together ended up
being too overwhelming and improving various aspects didn't end up helping that
much.
A result-based I/O error handling strategy also has shortcomings, but the
cognitive burden is much smaller. The tooling necessary to make this strategy as
usable as conditions were is much smaller than the tooling necessary for
conditions.
Perhaps conditions may manifest themselves as a future entity, but for now
we're going to remove them from the standard library.
Closes#9795Closes#8968
This has been a long time coming. Conditions in rust were initially envisioned
as being a good alternative to error code return pattern. The idea is that all
errors are fatal-by-default, and you can opt-in to handling the error by
registering an error handler.
While sounding nice, conditions ended up having some unforseen shortcomings:
* Actually handling an error has some very awkward syntax:
let mut result = None;
let mut answer = None;
io::io_error::cond.trap(|e| { result = Some(e) }).inside(|| {
answer = Some(some_io_operation());
});
match result {
Some(err) => { /* hit an I/O error */ }
None => {
let answer = answer.unwrap();
/* deal with the result of I/O */
}
}
This pattern can certainly use functions like io::result, but at its core
actually handling conditions is fairly difficult
* The "zero value" of a function is often confusing. One of the main ideas
behind using conditions was to change the signature of I/O functions. Instead
of read_be_u32() returning a result, it returned a u32. Errors were notified
via a condition, and if you caught the condition you understood that the "zero
value" returned is actually a garbage value. These zero values are often
difficult to understand, however.
One case of this is the read_bytes() function. The function takes an integer
length of the amount of bytes to read, and returns an array of that size. The
array may actually be shorter, however, if an error occurred.
Another case is fs::stat(). The theoretical "zero value" is a blank stat
struct, but it's a little awkward to create and return a zero'd out stat
struct on a call to stat().
In general, the return value of functions that can raise error are much more
natural when using a Result as opposed to an always-usable zero-value.
* Conditions impose a necessary runtime requirement on *all* I/O. In theory I/O
is as simple as calling read() and write(), but using conditions imposed the
restriction that a rust local task was required if you wanted to catch errors
with I/O. While certainly an surmountable difficulty, this was always a bit of
a thorn in the side of conditions.
* Functions raising conditions are not always clear that they are raising
conditions. This suffers a similar problem to exceptions where you don't
actually know whether a function raises a condition or not. The documentation
likely explains, but if someone retroactively adds a condition to a function
there's nothing forcing upstream users to acknowledge a new point of task
failure.
* Libaries using I/O are not guaranteed to correctly raise on conditions when an
error occurs. In developing various I/O libraries, it's much easier to just
return `None` from a read rather than raising an error. The silent contract of
"don't raise on EOF" was a little difficult to understand and threw a wrench
into the answer of the question "when do I raise a condition?"
Many of these difficulties can be overcome through documentation, examples, and
general practice. In the end, all of these difficulties added together ended up
being too overwhelming and improving various aspects didn't end up helping that
much.
A result-based I/O error handling strategy also has shortcomings, but the
cognitive burden is much smaller. The tooling necessary to make this strategy as
usable as conditions were is much smaller than the tooling necessary for
conditions.
Perhaps conditions may manifest themselves as a future entity, but for now
we're going to remove them from the standard library.
Closes#9795Closes#8968
- `extra::json` didn't make the cut, because of `extra::json` required
dep on `extra::TreeMap`. If/when `extra::TreeMap` moves out of `extra`,
then `extra::json` could move into `serialize`
- `libextra`, `libsyntax` and `librustc` depend on the newly created
`libserialize`
- The extensions to various `extra` types like `DList`, `RingBuf`, `TreeMap`
and `TreeSet` for `Encodable`/`Decodable` were moved into the respective
modules in `extra`
- There is some trickery, evident in `src/libextra/lib.rs` where a stub
of `extra::serialize` is set up (in `src/libextra/serialize.rs`) for
use in the stage0 build, where the snapshot rustc is still making
deriving for `Encodable` and `Decodable` point at extra. Big props to
@huonw for help working out the re-export solution for this
extra: inline extra::serialize stub
fix stuff clobbered in rebase + don't reexport serialize::serialize
no more globs in libserialize
syntax: fix import of libserialize traits
librustc: fix bad imports in encoder/decoder
add serialize dep to librustdoc
fix failing run-pass tests w/ serialize dep
adjust uuid dep
more rebase de-clobbering for libserialize
fixing tests, pushing libextra dep into cfg(test)
fix doc code in extra::json
adjust index.md links to serialize and uuid library
This removes @[] from the parser as well as much of the handling of it (and `@str`) from the compiler as I can find.
I've just rebased @pcwalton's (already reviewed) `@str` removal (and fixed the problems in a separate commit); the only new work is the trailing commits with my authorship.
Closes#11967
This is has been obsolete for quite a while now (including a release),
so removing the special handling seems fine. (The error message is quite
good still anyway.)
Fixes#9580.
`Times::times` was always a second-class loop because it did not support the `break` and `continue` operations. Its playful appeal was then lost after `do` was disabled for closures. It's time to let this one go.
cc #7621.
See the commit message. I'm not sure if we should merge this now, or wait until we can write `Clone::clone(x)` which will directly solve the above issue with perfect error messages.
This unfortunately changes an error like
error: mismatched types: expected `&&NotClone` but found `&NotClone`
into
error: type `NotClone` does not implement any method in scope named `clone`
I'd forgotten to update them when I changed this a while ago; it now displays error messages linked to the struct/variant field, rather than the `#[deriving(Trait)]` line, for all traits.
This also adds a very large number of autogenerated tests. I can easily remove/tone down that commit if necessary.
This makes error messages about (e.g.) `#[deriving(Clone)] struct Foo {
x: Type }` point at `x: Type` rather than `Clone` in the header (while
still referring to the `#[deriving(Clone)]` in the expansion info).
Now that procedural macros can be implemented outside of the compiler,
it's more important to have a reasonable API to work with. Here are the
basic changes:
* Rename SyntaxExpanderTTTrait to MacroExpander, SyntaxExpanderTT to
BasicMacroExpander, etc. I think "procedural macro" is the right
term for these now, right? The other option would be SynExtExpander
or something like that.
* Stop passing the SyntaxContext to extensions. This was only ever used
by macro_rules, which doesn't even use it anymore. I can't think of
a context in which an external extension would need it, and removal
allows the API to be significantly simpler - no more
SyntaxExpanderTTItemExpanderWithoutContext wrappers to worry about.
Now that procedural macros can be implemented outside of the compiler,
it's more important to have a reasonable API to work with. Here are the
basic changes:
* Rename SyntaxExpanderTTTrait to MacroExpander, SyntaxExpanderTT to
BasicMacroExpander, etc. I think "procedural macro" is the right
term for these now, right? The other option would be SynExtExpander
or something like that.
* Stop passing the SyntaxContext to extensions. This was only ever used
by macro_rules, which doesn't even use it anymore. I can't think of
a context in which an external extension would need it, and removal
allows the API to be significantly simpler - no more
SyntaxExpanderTTItemExpanderWithoutContext wrappers to worry about.
They all have to go into a single module at the moment unfortunately.
Ideally, the logging macros would live in std::logging, condition! would
live in std::condition, format! in std::fmt, etc. However, this
introduces cyclic dependencies between those modules and the macros they
use which the current expansion system can't deal with. We may be able
to get around this by changing the expansion phase to a two-pass system
but that's for a later PR.
Closes#2247
cc #11763
The old method of serializing the AST gives totally bogus spans if the
expansion of an imported macro causes compilation errors. The best
solution seems to be to serialize the actual textual macro definition
and load it the same way the std-macros are. I'm not totally confident
that getting the source from the CodeMap will always do the right thing,
but it seems to work in simple cases.
A mutable and immutable borrow place some restrictions on what you can
with the variable until the borrow ends. This commit attempts to convey
to the user what those restrictions are. Also, if the original borrow is
a mutable borrow, the error message has been changed (more specifically,
i. "cannot borrow `x` as immutable because it is also borrowed as
mutable" and ii. "cannot borrow `x` as mutable more than once" have
been changed to "cannot borrow `x` because it is already borrowed as
mutable").
In addition, this adds a (custom) span note to communicate where the
original borrow ends.
```rust
fn main() {
match true {
true => {
let mut x = 1;
let y = &x;
let z = &mut x;
}
false => ()
}
}
test.rs:6:21: 6:27 error: cannot borrow `x` as mutable because it is already borrowed as immutable
test.rs:6 let z = &mut x;
^~~~~~
test.rs:5:21: 5:23 note: previous borrow of `x` occurs here; the immutable borrow prevents subsequent moves or mutable borrows of `x` until the borrow ends
test.rs:5 let y = &x;
^~
test.rs:7:10: 7:10 note: previous borrow ends here
test.rs:3 true => {
test.rs:4 let mut x = 1;
test.rs:5 let y = &x;
test.rs:6 let z = &mut x;
test.rs:7 }
^
```
```rust
fn foo3(t0: &mut &mut int) {
let t1 = &mut *t0;
let p: &int = &**t0;
}
fn main() {}
test.rs:3:19: 3:24 error: cannot borrow `**t0` because it is already borrowed as mutable
test.rs:3 let p: &int = &**t0;
^~~~~
test.rs:2:14: 2:22 note: previous borrow of `**t0` as mutable occurs here; the mutable borrow prevents subsequent moves, borrows, or modification of `**t0` until the borrow ends
test.rs:2 let t1 = &mut *t0;
^~~~~~~~
test.rs:4:2: 4:2 note: previous borrow ends here
test.rs:1 fn foo3(t0: &mut &mut int) {
test.rs:2 let t1 = &mut *t0;
test.rs:3 let p: &int = &**t0;
test.rs:4 }
^
```
For the "previous borrow ends here" note, if the span is too long (has too many lines), then only the first and last lines are printed, and the middle is replaced with dot dot dot:
```rust
fn foo3(t0: &mut &mut int) {
let t1 = &mut *t0;
let p: &int = &**t0;
}
fn main() {}
test.rs:3:19: 3:24 error: cannot borrow `**t0` because it is already borrowed as mutable
test.rs:3 let p: &int = &**t0;
^~~~~
test.rs:2:14: 2:22 note: previous borrow of `**t0` as mutable occurs here; the mutable borrow prevents subsequent moves, borrows, or modification of `**t0` until the borrow ends
test.rs:2 let t1 = &mut *t0;
^~~~~~~~
test.rs:7:2: 7:2 note: previous borrow ends here
test.rs:1 fn foo3(t0: &mut &mut int) {
...
test.rs:7 }
^
```
(Sidenote: the `span_end_note` currently also has issue #11715)
Renamed the ```invert()``` function in ```iter.rs``` to ```flip()```, from #10632
Also renamed the ```Invert<T>``` type to ```Flip<T>```.
Some related code comments changed. Documentation that I could find has
been updated, and all the instances I could locate where the
function/type were called have been updated as well.
This is my first contribution to Rust! Apologies in advance if I've snarfed the
PR process, I'm not used to rebase.
I initially had issues with the ```codegen``` section of the tests failing, however
the ```make check``` process is not reporting any failures at this time. I think
that was a local env issue more than me facerolling my changes. :)
This patchset consists of three parts:
- rustpkg doesn't guess crate version if it is not given by user.
- `rustpkg::version::Version` is replaced by `Option<~str>`.
It removes some semantic versioning portions which is not currently used.
(cc #8405 and #11396)
`rustpkg::crate_id::CrateId` is also replaced by `syntax::crateid::CrateId`.
- rustpkg now computes hash to find crate, instead of manual filename parse.
cc @metajack
Renamed the invert() function in iter.rs to flip().
Also renamed the Invert<T> type to Flip<T>.
Some related code comments changed. Documentation that I could find has
been updated, and all the instances I could locate where the
function/type were called have been updated as well.
A mutable and immutable borrow place some restrictions on what you can
with the variable until the borrow ends. This commit attempts to convey
to the user what those restrictions are. Also, if the original borrow is
a mutable borrow, the error message has been changed (more specifically,
i. "cannot borrow `x` as immutable because it is also borrowed as
mutable" and ii. "cannot borrow `x` as mutable more than once" have
been changed to "cannot borrow `x` because it is already borrowed as
mutable").
In addition, this adds a (custom) span note to communicate where the
original borrow ends.
The old method of serializing the AST gives totally bogus spans if the
expansion of an imported macro causes compilation errors. The best
solution seems to be to serialize the actual textual macro definition
and load it the same way the std-macros are. I'm not totally confident
that getting the source from the CodeMap will always do the right thing,
but it seems to work in simple cases.
This means that compilation continues for longer, and so we can see more
errors per compile. This is mildly more user-friendly because it stops
users having to run rustc n times to see n macro errors: just run it
once to see all of them.
If the library is in the working directory, its path won't have a "/"
which will cause dlopen to search /usr/lib etc. It turns out that Path
auto-normalizes during joins so Path::new(".").join(path) is actually a
no-op.
NodeIds are sequential integers starting at zero, so we can achieve some
memory savings by just storing the items all in a line in a vector.
The occupancy for typical crates seems to be 75-80%, so we're already
more efficient than a HashMap (maximum occupancy 75%), not even counting
the extra book-keeping that HashMap does.
This commit re-works how the monitor() function works and how it both receives
and transmits errors. There are a few cases in which the compiler can abort:
1. A normal compiler error. In this case, the compiler raises a FatalError as
the failure value of the task. If this happens, then the monitor task does
nothing. It ignores all stderr output of the child task and it also
suppresses the failure message of the main task itself. This means that on a
normal compiler error just the error message itself is printed.
2. A normal internal compiler error. These are invoked from sess.span_bug() and
friends. In these cases, they follow the same path (raising a FatalError),
but they will also print an ICE message which has a URL to go report a bug.
3. An actual compiler bug. This happens whenever anything calls fail!() instead
of going through the session itself. In this case, we print out stuff about
RUST_LOG=2 and we by default capture all stderr and print via warn!() so it's
only printed out with the RUST_LOG var set.
For `use` statements, this means disallowing qualifiers when in functions and
disallowing `priv` outside of functions.
For `extern mod` statements, this means disallowing everything everywhere. It
may have been envisioned for `pub extern mod foo` to be a thing, but it
currently doesn't do anything (resolve doesn't pick it up), so better to err on
the side of forwards-compatibility and forbid it entirely for now.
Closes#9957
This commit re-works how the monitor() function works and how it both receives
and transmits errors. There are a few cases in which the compiler can abort:
1. A normal compiler error. In this case, the compiler raises a FatalError as
the failure value of the task. If this happens, then the monitor task does
nothing. It ignores all stderr output of the child task and it also
suppresses the failure message of the main task itself. This means that on a
normal compiler error just the error message itself is printed.
2. A normal internal compiler error. These are invoked from sess.span_bug() and
friends. In these cases, they follow the same path (raising a FatalError),
but they will also print an ICE message which has a URL to go report a bug.
3. An actual compiler bug. This happens whenever anything calls fail!() instead
of going through the session itself. In this case, we print out stuff about
RUST_LOG=2 and we by default capture all stderr and print via warn!() so it's
only printed out with the RUST_LOG var set.
For `use` statements, this means disallowing qualifiers when in functions and
disallowing `priv` outside of functions.
For `extern mod` statements, this means disallowing everything everywhere. It
may have been envisioned for `pub extern mod foo` to be a thing, but it
currently doesn't do anything (resolve doesn't pick it up), so better to err on
the side of forwards-compatibility and forbid it entirely for now.
Closes#9957
If the library is in the working directory, its path won't have a "/"
which will cause dlopen to search /usr/lib etc. It turns out that Path
auto-normalizes during joins so Path::new(".").join(path) is actually a
no-op.
* Reexport io::mem and io::buffered structs directly under io, make mem/buffered
private modules
* Remove with_mem_writer
* Remove DEFAULT_CAPACITY and use DEFAULT_BUF_SIZE (in io::buffered)
cc #11119
* Reexport io::mem and io::buffered structs directly under io, make mem/buffered
private modules
* Remove with_mem_writer
* Remove DEFAULT_CAPACITY and use DEFAULT_BUF_SIZE (in io::buffered)
Major changes:
- Define temporary scopes in a syntax-based way that basically defaults
to the innermost statement or conditional block, except for in
a `let` initializer, where we default to the innermost block. Rules
are documented in the code, but not in the manual (yet).
See new test run-pass/cleanup-value-scopes.rs for examples.
- Refactors Datum to better define cleanup roles.
- Refactor cleanup scopes to not be tied to basic blocks, permitting
us to have a very large number of scopes (one per AST node).
- Introduce nascent documentation in trans/doc.rs covering datums and
cleanup in a more comprehensive way.
r? @pcwalton
This means that compilation continues for longer, and so we can see more
errors per compile. This is mildly more user-friendly because it stops
users having to run rustc n times to see n macro errors: just run it
once to see all of them.
This is a first pass on support for procedural macros that aren't hardcoded into libsyntax. It is **not yet ready to merge** but I've opened a PR to have a chance to discuss some open questions and implementation issues.
Example
=======
Here's a silly example showing off the basics:
my_synext.rs
```rust
#[feature(managed_boxes, globs, macro_registrar, macro_rules)];
extern mod syntax;
use syntax::ast::{Name, token_tree};
use syntax::codemap::Span;
use syntax::ext::base::*;
use syntax::parse::token;
#[macro_export]
macro_rules! exported_macro (() => (2))
#[macro_registrar]
pub fn macro_registrar(register: |Name, SyntaxExtension|) {
register(token::intern(&"make_a_1"),
NormalTT(@SyntaxExpanderTT {
expander: SyntaxExpanderTTExpanderWithoutContext(expand_make_a_1),
span: None,
} as @SyntaxExpanderTTTrait,
None));
}
pub fn expand_make_a_1(cx: &mut ExtCtxt, sp: Span, tts: &[token_tree]) -> MacResult {
if !tts.is_empty() {
cx.span_fatal(sp, "make_a_1 takes no arguments");
}
MRExpr(quote_expr!(cx, 1i))
}
```
main.rs:
```rust
#[feature(phase)];
#[phase(syntax)]
extern mod my_synext;
fn main() {
assert_eq!(1, make_a_1!());
assert_eq!(2, exported_macro!());
}
```
Overview
=======
Crates that contain syntax extensions need to define a function with the following signature and annotation:
```rust
#[macro_registrar]
pub fn registrar(register: |ast::Name, ext::base::SyntaxExtension|) { ... }
```
that should call the `register` closure with each extension it defines. `macro_rules!` style macros can be tagged with `#[macro_export]` to be exported from the crate as well.
Crates that wish to use externally loadable syntax extensions load them by adding the `#[phase(syntax)]` attribute to an `extern mod`. All extensions registered by the specified crate are loaded with the same scoping rules as `macro_rules!` macros. If you want to use a crate both for syntax extensions and normal linkage, you can use `#[phase(syntax, link)]`.
Open questions
===========
* ~~Does the `macro_crate` syntax make sense? It wraps an entire `extern mod` declaration which looks a bit weird but is nice in the sense that the crate lookup logic can be identical between normal external crates and external macro crates. If the `extern mod` syntax, changes, this will get it for free, etc.~~ Changed to a `phase` attribute.
* ~~Is the magic name `macro_crate_registration` the right way to handle extension registration? It could alternatively be handled by a function annotated with `#[macro_registration]` I guess.~~ Switched to an attribute.
* The crate loading logic lives inside of librustc, which means that the syntax extension infrastructure can't directly access it. I've worked around this by passing a `CrateLoader` trait object from the driver to libsyntax that can call back into the crate loading logic. It should be possible to pull things apart enough that this isn't necessary anymore, but it will be an enormous refactoring project. I think we'll need to create a couple of new libraries: libsynext libmetadata/ty and libmiddle.
* Item decorator extensions can be loaded but the `deriving` decorator itself can't be extended so you'd need to do e.g. `#[deriving_MyTrait] #[deriving(Clone)]` instead of `#[deriving(MyTrait, Clone)]`. Is this something worth bothering with for now?
Remaining work
===========
- [x] ~~There is not yet support for rustdoc downloading and compiling referenced macro crates as it does for other referenced crates. This shouldn't be too hard I think.~~
- [x] ~~This is not testable at stage1 and sketchily testable at stages above that. The stage *n* rustc links against the stage *n-1* libsyntax and librustc. Unfortunately, crates in the test/auxiliary directory link against the stage *n* libstd, libextra, libsyntax, etc. This causes macro crates to fail to properly dynamically link into rustc since names end up being mangled slightly differently. In addition, when rustc is actually installed onto a system, there are actually do copies of libsyntax, libstd, etc: the ones that user code links against and a separate set from the previous stage that rustc itself uses. By this point in the bootstrap process, the two library versions *should probably* be binary compatible, but it doesn't seem like a sure thing. Fixing this is apparently hard, but necessary to properly cross compile as well and is being tracked in #11145.~~ The offending tests are ignored during `check-stage1-rpass` and `check-stage1-cfail`. When we get a snapshot that has this commit, I'll look into how feasible it'll be to get them working on stage1.
- [x] ~~`macro_rules!` style macros aren't being exported. Now that the crate loading infrastructure is there, this should just require serializing the AST of the macros into the crate metadata and yanking them out again, but I'm not very familiar with that part of the compiler.~~
- [x] ~~The `macro_crate_registration` function isn't type-checked when it's loaded. I poked around in the `csearch` infrastructure a bit but didn't find any super obvious ways of checking the type of an item with a certain name. Fixing this may also eliminate the need to `#[no_mangle]` the registration function.~~ Now that the registration function is identified by an attribute, typechecking this will be like typechecking other annotated functions.
- [x] ~~The dynamic libraries that are loaded are never unloaded. It shouldn't require too much work to tie the lifetime of the `DynamicLibrary` object to the `MapChain` that its extensions are loaded into.~~
- [x] ~~The compiler segfaults sometimes when loading external crates. The `DynamicLibrary` reference and code objects from that library are both put into the same hash table. When the table drops, due to the random ordering the library sometimes drops before the objects do. Once #11228 lands it'll be easy to fix this.~~
Major changes:
- Define temporary scopes in a syntax-based way that basically defaults
to the innermost statement or conditional block, except for in
a `let` initializer, where we default to the innermost block. Rules
are documented in the code, but not in the manual (yet).
See new test run-pass/cleanup-value-scopes.rs for examples.
- Refactors Datum to better define cleanup roles.
- Refactor cleanup scopes to not be tied to basic blocks, permitting
us to have a very large number of scopes (one per AST node).
- Introduce nascent documentation in trans/doc.rs covering datums and
cleanup in a more comprehensive way.
