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Add support for the % format code for floats. #1657

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Merged
merged 1 commit into from
Jan 4, 2020
Merged

Add support for the % format code for floats. #1657

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14 changes: 14 additions & 0 deletions tests/snippets/strings.py
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Original file line number Diff line number Diff line change
Expand Up @@ -431,3 +431,17 @@ def try_mutate_str():
assert f'{1234567890.1234:_.2f}' == '1_234_567_890.12'
with AssertRaises(ValueError, msg="Unknown format code 'd' for object of type 'float'"):
f'{5.0:04d}'

# Test % formatting
assert f'{10.0:%}' == '1000.000000%'
assert f'{10.0:.2%}' == '1000.00%'
assert f'{10.0:.8%}' == '1000.00000000%'
assert f'{-10.0:%}' == '-1000.000000%'
assert f'{-10.0:.2%}' == '-1000.00%'
assert f'{-10.0:.8%}' == '-1000.00000000%'
assert '{:%}'.format(float('nan')) == 'nan%'
assert '{:.2%}'.format(float('nan')) == 'nan%'
assert '{:%}'.format(float('inf')) == 'inf%'
assert '{:.2%}'.format(float('inf')) == 'inf%'
with AssertRaises(ValueError, msg='Invalid format specifier'):
f'{10.0:%3}'
76 changes: 57 additions & 19 deletions vm/src/format.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,7 @@ pub enum FormatType {
GeneralFormatUpper,
FixedPointLower,
FixedPointUpper,
Percentage,
}

#[derive(Debug, PartialEq)]
Expand Down Expand Up @@ -232,11 +233,12 @@ fn parse_format_type(text: &str) -> (Option<FormatType>, &str) {
Some('g') => (Some(FormatType::GeneralFormatLower), chars.as_str()),
Some('G') => (Some(FormatType::GeneralFormatUpper), chars.as_str()),
Some('n') => (Some(FormatType::Number), chars.as_str()),
Some('%') => (Some(FormatType::Percentage), chars.as_str()),
_ => (None, text),
}
}

fn parse_format_spec(text: &str) -> FormatSpec {
fn parse_format_spec(text: &str) -> Result<FormatSpec, &'static str> {
let (preconversor, after_preconversor) = parse_preconversor(text);
let (mut fill, mut align, after_align) = parse_fill_and_align(after_preconversor);
let (sign, after_sign) = parse_sign(after_align);
Expand All @@ -245,14 +247,17 @@ fn parse_format_spec(text: &str) -> FormatSpec {
let (width, after_width) = parse_number(after_zero);
let (grouping_option, after_grouping_option) = parse_grouping_option(after_width);
let (precision, after_precision) = parse_precision(after_grouping_option);
let (format_type, _) = parse_format_type(after_precision);
let (format_type, after_format_type) = parse_format_type(after_precision);
if !after_format_type.is_empty() {
return Err("Invalid format specifier");
}
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Maybe add some tests that ensure that this properly fails with characters left after the format type.

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👍


if zero && fill.is_none() {
fill.replace('0');
align = align.or(Some(FormatAlign::AfterSign));
}

FormatSpec {
Ok(FormatSpec {
preconversor,
fill,
align,
Expand All @@ -262,11 +267,11 @@ fn parse_format_spec(text: &str) -> FormatSpec {
grouping_option,
precision,
format_type,
}
})
}

impl FormatSpec {
pub fn parse(text: &str) -> FormatSpec {
pub fn parse(text: &str) -> Result<FormatSpec, &'static str> {
parse_format_spec(text)
}

Expand Down Expand Up @@ -369,6 +374,11 @@ impl FormatSpec {
Some(FormatType::ExponentLower) => {
Err("Format code 'e' for object of type 'float' not implemented yet")
}
Some(FormatType::Percentage) => match magnitude {
magnitude if magnitude.is_nan() => Ok("nan%".to_string()),
magnitude if magnitude.is_infinite() => Ok("inf%".to_string()),
_ => Ok(format!("{:.*}%", precision, magnitude * 100.0)),
},
None => {
match magnitude {
magnitude if magnitude.is_nan() => Ok("nan".to_string()),
Expand Down Expand Up @@ -443,6 +453,9 @@ impl FormatSpec {
_ => Err("Unable to convert int to float"),
}
}
Some(FormatType::Percentage) => {
Err("Format code '%' for object of type 'int' not implemented yet")
}
None => Ok(magnitude.to_str_radix(10)),
};
if raw_magnitude_string_result.is_err() {
Expand Down Expand Up @@ -525,7 +538,7 @@ pub enum FormatParseError {
impl FromStr for FormatSpec {
type Err = &'static str;
fn from_str(s: &str) -> Result<Self, Self::Err> {
Ok(FormatSpec::parse(s))
FormatSpec::parse(s)
}
}

Expand Down Expand Up @@ -702,7 +715,7 @@ mod tests {

#[test]
fn test_width_only() {
let expected = FormatSpec {
let expected = Ok(FormatSpec {
preconversor: None,
fill: None,
align: None,
Expand All @@ -712,13 +725,13 @@ mod tests {
grouping_option: None,
precision: None,
format_type: None,
};
});
assert_eq!(parse_format_spec("33"), expected);
}

#[test]
fn test_fill_and_width() {
let expected = FormatSpec {
let expected = Ok(FormatSpec {
preconversor: None,
fill: Some('<'),
align: Some(FormatAlign::Right),
Expand All @@ -728,13 +741,13 @@ mod tests {
grouping_option: None,
precision: None,
format_type: None,
};
});
assert_eq!(parse_format_spec("<>33"), expected);
}

#[test]
fn test_all() {
let expected = FormatSpec {
let expected = Ok(FormatSpec {
preconversor: None,
fill: Some('<'),
align: Some(FormatAlign::Right),
Expand All @@ -744,38 +757,52 @@ mod tests {
grouping_option: Some(FormatGrouping::Comma),
precision: Some(11),
format_type: Some(FormatType::Binary),
};
});
assert_eq!(parse_format_spec("<>-#23,.11b"), expected);
}

#[test]
fn test_format_int() {
assert_eq!(
parse_format_spec("d").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
parse_format_spec("d")
.unwrap()
.format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("16".to_string())
);
assert_eq!(
parse_format_spec("x").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
parse_format_spec("x")
.unwrap()
.format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("10".to_string())
);
assert_eq!(
parse_format_spec("b").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
parse_format_spec("b")
.unwrap()
.format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("10000".to_string())
);
assert_eq!(
parse_format_spec("o").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
parse_format_spec("o")
.unwrap()
.format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("20".to_string())
);
assert_eq!(
parse_format_spec("+d").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
parse_format_spec("+d")
.unwrap()
.format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("+16".to_string())
);
assert_eq!(
parse_format_spec("^ 5d").format_int(&BigInt::from_bytes_be(Sign::Minus, b"\x10")),
parse_format_spec("^ 5d")
.unwrap()
.format_int(&BigInt::from_bytes_be(Sign::Minus, b"\x10")),
Ok(" -16 ".to_string())
);
assert_eq!(
parse_format_spec("0>+#10x").format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
parse_format_spec("0>+#10x")
.unwrap()
.format_int(&BigInt::from_bytes_be(Sign::Plus, b"\x10")),
Ok("00000+0x10".to_string())
);
}
Expand Down Expand Up @@ -814,4 +841,15 @@ mod tests {

assert_eq!(FormatString::from_str("{{{key}}}ddfe"), expected);
}

#[test]
fn test_format_invalid_specification() {
assert_eq!(parse_format_spec("%3"), Err("Invalid format specifier"));
assert_eq!(parse_format_spec(".2fa"), Err("Invalid format specifier"));
assert_eq!(parse_format_spec("ds"), Err("Invalid format specifier"));
assert_eq!(parse_format_spec("x+"), Err("Invalid format specifier"));
assert_eq!(parse_format_spec("b4"), Err("Invalid format specifier"));
assert_eq!(parse_format_spec("o!"), Err("Invalid format specifier"));
assert_eq!(parse_format_spec("d "), Err("Invalid format specifier"));
}
}
5 changes: 3 additions & 2 deletions vm/src/obj/objfloat.rs
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Expand Up @@ -213,8 +213,9 @@ impl PyFloat {

#[pymethod(name = "__format__")]
fn format(&self, spec: PyStringRef, vm: &VirtualMachine) -> PyResult<String> {
let format_spec = FormatSpec::parse(spec.as_str());
match format_spec.format_float(self.value) {
match FormatSpec::parse(spec.as_str())
.and_then(|format_spec| format_spec.format_float(self.value))
{
Ok(string) => Ok(string),
Err(err) => Err(vm.new_value_error(err.to_string())),
}
Expand Down
5 changes: 3 additions & 2 deletions vm/src/obj/objint.rs
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Expand Up @@ -506,8 +506,9 @@ impl PyInt {

#[pymethod(name = "__format__")]
fn format(&self, spec: PyStringRef, vm: &VirtualMachine) -> PyResult<String> {
let format_spec = FormatSpec::parse(spec.as_str());
match format_spec.format_int(&self.value) {
match FormatSpec::parse(spec.as_str())
.and_then(|format_spec| format_spec.format_int(&self.value))
{
Ok(string) => Ok(string),
Err(err) => Err(vm.new_value_error(err.to_string())),
}
Expand Down