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Merged
merged 3 commits into from
Feb 9, 2019
Merged

Add reversed builtin and range.__reversed__ #385

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1ebacaf
Add reversed builtin and range.__reversed__
OddCoincidence Feb 8, 2019
969ddf2
Merge remote-tracking branch 'upstream/master' into reversed
OddCoincidence Feb 9, 2019
22a430c
Don't use magic methods directly
OddCoincidence Feb 9, 2019
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32 changes: 18 additions & 14 deletions tests/snippets/builtin_range.py
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Original file line number Diff line number Diff line change
Expand Up @@ -40,20 +40,24 @@ def assert_raises(expr, exc_type):
assert_raises(lambda _: range(10).index('foo'), ValueError)

# __bool__
assert range(1).__bool__()
assert range(1, 2).__bool__()
assert bool(range(1))
assert bool(range(1, 2))

assert not range(0).__bool__()
assert not range(1, 1).__bool__()
assert not bool(range(0))
assert not bool(range(1, 1))

# __contains__
assert range(10).__contains__(6)
assert range(4, 10).__contains__(6)
assert range(4, 10, 2).__contains__(6)
assert range(10, 4, -2).__contains__(10)
assert range(10, 4, -2).__contains__(8)

assert not range(10).__contains__(-1)
assert not range(10, 4, -2).__contains__(9)
assert not range(10, 4, -2).__contains__(4)
assert not range(10).__contains__('foo')
assert 6 in range(10)
assert 6 in range(4, 10)
assert 6 in range(4, 10, 2)
assert 10 in range(10, 4, -2)
assert 8 in range(10, 4, -2)

assert -1 not in range(10)
assert 9 not in range(10, 4, -2)
assert 4 not in range(10, 4, -2)
assert 'foo' not in range(10)

# __reversed__
assert list(reversed(range(5))) == [4, 3, 2, 1, 0]
assert list(reversed(range(5, 0, -1))) == [1, 2, 3, 4, 5]
1 change: 1 addition & 0 deletions tests/snippets/builtin_reversed.py
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@@ -0,0 +1 @@
assert list(reversed(range(5))) == [4, 3, 2, 1, 0]
14 changes: 14 additions & 0 deletions vm/src/builtins.rs
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Expand Up @@ -587,6 +587,19 @@ fn builtin_repr(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
arg_check!(vm, args, required = [(obj, None)]);
vm.to_repr(obj)
}

fn builtin_reversed(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
arg_check!(vm, args, required = [(obj, None)]);

match vm.get_method(obj.clone(), "__reversed__") {
Ok(value) => vm.invoke(value, PyFuncArgs::default()),
// TODO: fallback to using __len__ and __getitem__, if object supports sequence protocol
Err(..) => Err(vm.new_type_error(format!(
"'{}' object is not reversible",
objtype::get_type_name(&obj.typ()),
))),
}
}
// builtin_reversed

fn builtin_round(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
Expand Down Expand Up @@ -692,6 +705,7 @@ pub fn make_module(ctx: &PyContext) -> PyObjectRef {
ctx.set_attr(&py_mod, "property", ctx.property_type());
ctx.set_attr(&py_mod, "range", ctx.range_type());
ctx.set_attr(&py_mod, "repr", ctx.new_rustfunc(builtin_repr));
ctx.set_attr(&py_mod, "reversed", ctx.new_rustfunc(builtin_reversed));
ctx.set_attr(&py_mod, "round", ctx.new_rustfunc(builtin_round));
ctx.set_attr(&py_mod, "set", ctx.set_type());
ctx.set_attr(&py_mod, "setattr", ctx.new_rustfunc(builtin_setattr));
Expand Down
38 changes: 38 additions & 0 deletions vm/src/obj/objrange.rs
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Expand Up @@ -94,6 +94,22 @@ impl RangeType {
}

#[inline]
pub fn reversed(&self) -> Self {
match self.step.sign() {
Sign::Plus => RangeType {
start: &self.end - 1,
end: &self.start - 1,
step: -&self.step,
},
Sign::Minus => RangeType {
start: &self.end + 1,
end: &self.start + 1,
step: -&self.step,
},
Sign::NoSign => unreachable!(),
}
}

pub fn repr(&self) -> String {
if self.step == BigInt::one() {
format!("range({}, {})", self.start, self.end)
Expand All @@ -116,6 +132,11 @@ pub fn init(context: &PyContext) {

context.set_attr(&range_type, "__new__", context.new_rustfunc(range_new));
context.set_attr(&range_type, "__iter__", context.new_rustfunc(range_iter));
context.set_attr(
&range_type,
"__reversed__",
context.new_rustfunc(range_reversed),
);
context.set_attr(
&range_type,
"__doc__",
Expand Down Expand Up @@ -190,6 +211,23 @@ fn range_iter(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
))
}

fn range_reversed(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
arg_check!(vm, args, required = [(zelf, Some(vm.ctx.range_type()))]);

let range = match zelf.borrow().payload {
PyObjectPayload::Range { ref range } => range.reversed(),
_ => unreachable!(),
};

Ok(PyObject::new(
PyObjectPayload::Iterator {
position: 0,
iterated_obj: PyObject::new(PyObjectPayload::Range { range }, vm.ctx.range_type()),
},
vm.ctx.iter_type(),
))
}

fn range_len(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
arg_check!(vm, args, required = [(zelf, Some(vm.ctx.range_type()))]);

Expand Down