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Implement __sub__/__rsub__. #188

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Merged
merged 3 commits into from
Nov 6, 2018
Merged

Implement __sub__/__rsub__. #188

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0f0de02
Implement __sub__/__rsub__.
cthulahoops Nov 4, 2018
60f2914
Add test for class with sub and rsub.
cthulahoops Nov 4, 2018
bacaef0
Make example work for sub/rsub. Still work in progress.
windelbouwman Nov 6, 2018
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21 changes: 21 additions & 0 deletions tests/snippets/subtraction.py
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Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
assert 5 - 3 == 2

class Complex():
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Note complex builtin type is also present, no issue here though.

def __init__(self, real, imag):
self.real = real
self.imag = imag

def __repr__(self):
return "Com" + str((self.real, self.imag))

def __sub__(self, other):
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Good check! Here lies the proof of the pudding indeed!

return Complex(self.real - other, self.imag)

def __rsub__(self, other):
return Complex(other - self.real, -self.imag)

def __eq__(self, other):
return self.real == other.real and self.imag == other.imag

assert Complex(4, 5) - 3 == Complex(1, 5)
assert 7 - Complex(4, 5) == Complex(3, -5)
2 changes: 1 addition & 1 deletion vm/src/obj/objint.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -226,7 +226,7 @@ fn int_sub(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
.ctx
.new_float(i.to_f64().unwrap() - objfloat::get_value(i2)))
} else {
Err(vm.new_type_error(format!("Cannot substract {:?} and {:?}", i, i2)))
Err(vm.new_not_implemented_error(format!("Cannot substract {:?} and {:?}", i, i2)))
}
}

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64 changes: 48 additions & 16 deletions vm/src/vm.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -78,6 +78,11 @@ impl VirtualMachine {
self.new_exception(value_error, msg)
}

pub fn new_not_implemented_error(&mut self, msg: String) -> PyObjectRef {
let value_error = self.ctx.exceptions.not_implemented_error.clone();
self.new_exception(value_error, msg)
}

pub fn new_scope(&mut self, parent_scope: Option<PyObjectRef>) -> PyObjectRef {
// let parent_scope = self.current_frame_mut().locals.clone();
self.ctx.new_scope(parent_scope)
Expand Down Expand Up @@ -437,23 +442,50 @@ impl VirtualMachine {
}

pub fn _sub(&mut self, a: PyObjectRef, b: PyObjectRef) -> PyResult {
// Try __sub__, next __rsub__, next, give up
self.call_method(&a, "__sub__", vec![b])
/*
if a.has_attr("__sub__") {
self.call_method(&a, "__sub__", vec![b])
} else if b.has_attr("__rsub__") {
self.call_method(&b, "__rsub__", vec![a])
} else {
// Cannot sub a and b
let a_type_name = objtype::get_type_name(&a.typ());
let b_type_name = objtype::get_type_name(&b.typ());
Err(self.new_type_error(format!(
"Unsupported operand types for '-': '{}' and '{}'",
a_type_name, b_type_name
)))
// 1. Try __sub__, next __rsub__, next, give up
if let Ok(method) = self.get_method(a.clone(), "__sub__") {
match self.invoke(
method,
PyFuncArgs {
args: vec![b.clone()],
kwargs: vec![],
},
) {
Ok(value) => return Ok(value),
Err(err) => {
if !objtype::isinstance(&err, &self.ctx.exceptions.not_implemented_error) {
return Err(err);
}
}
}
}
*/

// 2. try __rsub__
if let Ok(method) = self.get_method(b.clone(), "__rsub__") {
match self.invoke(
method,
PyFuncArgs {
args: vec![a.clone()],
kwargs: vec![],
},
) {
Ok(value) => return Ok(value),
Err(err) => {
if !objtype::isinstance(&err, &self.ctx.exceptions.not_implemented_error) {
return Err(err);
}
}
}
}

// 3. It all failed :(
// Cannot sub a and b
let a_type_name = objtype::get_type_name(&a.typ());
let b_type_name = objtype::get_type_name(&b.typ());
Err(self.new_type_error(format!(
"Unsupported operand types for '-': '{}' and '{}'",
a_type_name, b_type_name
)))
}

pub fn _add(&mut self, a: PyObjectRef, b: PyObjectRef) -> PyResult {
Expand Down