8000 Add __length_hint__ support for iterators by coolreader18 · Pull Request #1666 · RustPython/RustPython · GitHub
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Add __length_hint__ support for iterators #1666

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Merged
merged 5 commits into from
Jan 10, 2020
Merged

Add __length_hint__ support for iterators #1666

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6b537f1
Add objsequence::{opt_,}len
coolreader18 Dec 29, 2019
fc3ac16
Add length_hint functionality
coolreader18 Dec 29, 2019
c65dc33
Add _operator module
coolreader18 Dec 29, 2019
098393d
Add __length_hint__ to a bunch of iterators
coolreader18 Jan 3, 2020
a26e5f2
Add dict iterator __length_hint__
coolreader18 Jan 3, 2020
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Add __length_hint__ to a bunch of iterators
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@coolreader18
coolreader18 committed Jan 10, 2020
commit 098393d4d6e4db91d31868800ef7431535825971
14 changes: 14 additions & 0 deletions vm/src/obj/objiter.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -172,6 +172,20 @@ impl PySequenceIterator {
fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
zelf
}

#[pymethod(name = "__length_hint__")]
fn length_hint(&self, vm: &VirtualMachine) -> PyResult<isize> {
let pos = self.position.get();
let hint = if self.reversed {
pos + 1
} else {
let len = objsequence::opt_len(&self.obj, vm).unwrap_or_else(|| {
Err(vm.new_type_error("sequence has no __len__ method".to_string()))
})?;
len as isize - pos
};
Ok(hint)
}
}

pub fn seq_iter_method(obj: PyObjectRef, _vm: &VirtualMachine) -> PySequenceIterator {
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10 changes: 10 additions & 0 deletions vm/src/obj/objlist.rs
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Expand Up @@ -873,6 +873,11 @@ impl PyListIterator {
fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
zelf
}

#[pymethod(name = "__length_hint__")]
fn length_hint(&self, _vm: &VirtualMachine) -> usize {
self.list.elements.borrow().len() - self.position.get()
}
}

#[pyclass]
Expand Down Expand Up @@ -906,6 +911,11 @@ impl PyListReverseIterator {
fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
zelf
}

#[pymethod(name = "__length_hint__")]
fn length_hint(&self, _vm: &VirtualMachine) -> usize {
self.position.get()
}
}

pub fn init(context: &PyContext) {
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9 changes: 9 additions & 0 deletions vm/src/obj/objmap.rs
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Expand Up @@ -58,6 +58,15 @@ impl PyMap {
fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
zelf
}

#[pymethod(name = "__length_hint__")]
fn length_hint(&self, vm: &VirtualMachine) -> PyResult<usize> {
self.iterators.iter().try_fold(0, |prev, cur| {
let cur = objiter::length_hint(vm, cur.clone())?.unwrap_or(0);
let max = std::cmp::max(prev, cur);
Ok(max)
})
}
}

pub fn init(context: &PyContext) {
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4 changes: 2 additions & 2 deletions vm/src/obj/objrange.rs
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Expand Up @@ -210,8 +210,8 @@ impl PyRange {
}

#[pymethod(name = "__len__")]
fn len(&self, _vm: &VirtualMachine) -> PyInt {
PyInt::new(self.length())
fn len(&self, _vm: &VirtualMachine) -> BigInt {
self.length()
}

#[pymethod(name = "__repr__")]
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34 changes: 17 additions & 17 deletions vm/src/stdlib/itertools.rs
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@@ -1,12 +1,9 @@
use std::cell::{Cell, RefCell};
use std::cmp::Ordering;
use std::iter;
use std::ops::{AddAssign, SubAssign};
use std::rc::Rc;

use num_bigint::BigInt;
use num_traits::sign::Signed;
use num_traits::ToPrimitive;
use num_traits::{One, Signed, ToPrimitive, Zero};

use crate::function::{Args, OptionalArg, OptionalOption, PyFuncArgs};
use crate::obj::objbool;
Expand Down Expand Up @@ -166,11 +163,11 @@ impl PyItertoolsCount {
) -> PyResult<PyRef<Self>> {
let start = match start.into_option() {
Some(int) => int.as_bigint().clone(),
None => BigInt::from(0),
None => BigInt::zero(),
};
let step = match step.into_option() {
Some(int) => int.as_bigint().clone(),
None => BigInt::from(1),
None => BigInt::one(),
};

PyItertoolsCount {
Expand All @@ -183,7 +180,7 @@ impl PyItertoolsCount {
#[pymethod(name = "__next__")]
fn next(&self, _vm: &VirtualMachine) -> PyResult<PyInt> {
let result = self.cur.borrow().clone();
AddAssign::add_assign(&mut self.cur.borrow_mut() as &mut BigInt, &self.step);
*self.cur.borrow_mut() += &self.step;
Ok(PyInt::new(result))
}

Expand Down Expand Up @@ -296,16 +293,11 @@ impl PyItertoolsRepeat {

#[pymethod(name = "__next__")]
fn next(&self, vm: &VirtualMachine) -> PyResult {
if self.times.is_some() {
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Nice :)

match self.times.as_ref().unwrap().borrow().cmp(&BigInt::from(0)) {
Ordering::Less | Ordering::Equal => return Err(new_stop_iteration(vm)),
_ => (),
};

SubAssign::sub_assign(
&mut self.times.as_ref().unwrap().borrow_mut() as &mut BigInt,
&BigInt::from(1),
);
if let Some(ref times) = self.times {
if *times.borrow() <= BigInt::zero() {
return Err(new_stop_iteration(vm));
}
*times.borrow_mut() -= 1;
}

Ok(self.object.clone())
Expand All @@ -315,6 +307,14 @@ impl PyItertoolsRepeat {
fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
zelf
}

#[pymethod(name = "__length_hint__")]
fn length_hint(&self, vm: &VirtualMachine) -> PyObjectRef {
match self.times {
Some(ref times) => vm.new_int(times.borrow().clone()),
None => vm.new_int(0),
}
}
}

#[pyclass(name = "starmap")]
Expand Down
0