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parse vulgar fractions
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@feefladder
feefladder committed Feb 7, 2024
1 parent 29207bb commit 703b26f
Showing 1 changed file with 121 additions and 42 deletions.
163 changes: 121 additions & 42 deletions src/fraction/unicode_fromto_str.rs
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Original file line number Diff line number Diff line change
@@ -1,12 +1,12 @@
use std::fmt::Display;

use crate::fraction::GenericFraction;
use std::{fmt, str};
use crate::{error::ParseError, Sign};
use num::rational::Ratio;
use std::{fmt, str};
use Integer;

impl<T: Clone + Integer + Display> GenericFraction<T> {
impl<T: Clone + Integer + Display + From<u8>> GenericFraction<T> {
pub fn unicode_display(&self) -> impl fmt::Display + '_ {
struct UnicodeDisplay<'a, T: Clone + Integer>(&'a GenericFraction<T>);
impl<'a, T> fmt::Display for UnicodeDisplay<'a, T>
Expand Down Expand Up @@ -36,14 +36,21 @@ impl<T: Clone + Integer + Display> GenericFraction<T> {
struct S<'a, T: Clone + Integer + fmt::Display>(&'a GenericFraction<T>);
impl<'a, T> fmt::Display for S<'a, T>
where
T: Clone + Integer + fmt::Display,
T: Clone + Integer + fmt::Display + From<u8>,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match &self.0 {
GenericFraction::Rational(s, r) if r.fract() != *r && !r.denom().is_one() => {
write!(f, "{}{}\u{2064}{}⁄{}", s, r.trunc().numer(), r.fract().numer(), r.fract().denom())
GenericFraction::Rational(s, r) if r.fract() != *r && !r.denom().is_one() => {
write!(
f,
"{}{}\u{2064}{}⁄{}",
s,
r.trunc().numer(),
r.fract().numer(),
r.fract().denom()
)
}
_ => write!(f, "{}", self.0.unicode_display())
_ => write!(f, "{}", self.0.unicode_display()),
}
}
}
Expand All @@ -55,7 +62,6 @@ impl<T: Clone + Integer + Display> GenericFraction<T> {
let sign = if input.starts_with('-') {
s = &input[1..];
Sign::Minus

} else if input.starts_with('+') {
s = &input[1..];
Sign::Plus
Expand All @@ -65,20 +71,40 @@ impl<T: Clone + Integer + Display> GenericFraction<T> {
};
if s.to_lowercase().starts_with("nan") {
Ok(GenericFraction::nan())
} else if s.starts_with("∞")
|| s.starts_with("inf")
|| s.starts_with("infty")
{
} else if s.starts_with("∞") || s.starts_with("inf") || s.starts_with("infty") {
Ok(GenericFraction::Infinity(sign))
// vulgar fractions
} else if s.starts_with("½") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(1.into(), 2.into())))
} else if s.starts_with("¼") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(1.into(), 4.into())))
} else if s.starts_with("¾") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(3.into(), 4.into())))
} else if s.starts_with("⅐") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(1.into(), 7.into())))
} else if s.starts_with("⅑") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(1.into(), 9.into())))
} else if s.starts_with("⅒") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(1.into(), 10.into())))
} else if s.starts_with("⅓") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(1.into(), 3.into())))
} else if s.starts_with("⅔") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(2.into(), 3.into())))
} else if s.starts_with("⅕") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(1.into(), 5.into())))
} else if s.starts_with("⅖") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(2.into(), 5.into())))
} else if s.starts_with("⅗") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(3.into(), 5.into())))
} else if s.starts_with("⅘") {
Ok(GenericFraction::Rational(sign, Ratio::new_raw(4.into(), 5.into())))
} else if let Some((first, denom_str)) = s.split_once(&['/', '⁄', '∕', '÷'][..]) {
// also allow for mixed fractions to be parsed: `1⁤1⁄2`
// allowed invisible separators: \u{2064} \u{2063}
// '+' is disallowed, bc it would be confusing with -1+1/2
let mut numer: T;
let denom: T;
if let Some((trunc_str, numer_str)) =
first.split_once(&['\u{2064}', '\u{2063}'][..])
{
if let Some((trunc_str, numer_str)) = first.split_once(&['\u{2064}', '\u{2063}'][..]) {
let Ok(n) = T::from_str_radix(numer_str, 10) else {
return Err(ParseError::ParseIntError);
};
Expand All @@ -102,18 +128,12 @@ impl<T: Clone + Integer + Display> GenericFraction<T> {
};
denom = d;
}
Ok(GenericFraction::Rational(
sign,
Ratio::new(numer, denom),
))
Ok(GenericFraction::Rational(sign, Ratio::new(numer, denom)))
} else {
let Ok(val) = T::from_str_radix(&s, 10) else {
return Err(ParseError::ParseIntError);
};
Ok(GenericFraction::Rational(
sign,
Ratio::new(val, T::one()),
))
Ok(GenericFraction::Rational(sign, Ratio::new(val, T::one())))
}
}
}
Expand All @@ -123,9 +143,7 @@ mod tests {

use num::{One, Zero};

use crate::{
error::ParseError, Fraction,
};
use crate::{error::ParseError, Fraction};

#[test]
fn test_fromto_str() {
Expand All @@ -141,6 +159,7 @@ mod tests {
("-1⁄2", Fraction::new_neg(1u8, 2u8)),
("3⁄2", Fraction::new(3u8, 2u8)),
("-3⁄2", Fraction::new_neg(3u8, 2u8)),
("12⁄23", Fraction::new(12u8, 23u8)),
];
for (string, frac) in test_vec {
println!("{} ?= {}", string, frac);
Expand All @@ -151,7 +170,78 @@ mod tests {
}

#[test]
fn test_fromto_str_mixed() {
fn test_alternate_parse() {
let test_vec = vec![
("nan", Fraction::nan()),
("+∞", Fraction::infinity()),
("+1", Fraction::one()),
("+5", Fraction::from(5)),
// vulgar fractions
("½", Fraction::new (1u8, 2u8)),
("-½", Fraction::new_neg(1u8, 2u8)),
("+½", Fraction::new (1u8, 2u8)),
("¼", Fraction::new (1u8, 4u8)),
("-¼", Fraction::new_neg(1u8, 4u8)),
("+¼", Fraction::new (1u8, 4u8)),
("¾", Fraction::new (3u8, 4u8)),
("-¾", Fraction::new_neg(3u8, 4u8)),
("+¾", Fraction::new (3u8, 4u8)),
("⅐", Fraction::new (1u8, 7u8)),
("-⅐", Fraction::new_neg(1u8, 7u8)),
("+⅐", Fraction::new (1u8, 7u8)),
("⅑", Fraction::new (1u8, 9u8)),
("-⅑", Fraction::new_neg(1u8, 9u8)),
("+⅑", Fraction::new (1u8, 9u8)),
("⅒", Fraction::new (1u8, 10u8)),
("-⅒", Fraction::new_neg(1u8, 10u8)),
("+⅒", Fraction::new (1u8, 10u8)),
("⅓", Fraction::new (1u8, 3u8)),
("-⅓", Fraction::new_neg(1u8, 3u8)),
("+⅓", Fraction::new (1u8, 3u8)),
("⅔", Fraction::new (2u8, 3u8)),
("-⅔", Fraction::new_neg(2u8, 3u8)),
("+⅔", Fraction::new (2u8, 3u8)),
("⅕", Fraction::new (1u8, 5u8)),
("-⅕", Fraction::new_neg(1u8, 5u8)),
("+⅕", Fraction::new (1u8, 5u8)),
("⅖", Fraction::new (2u8, 5u8)),
("-⅖", Fraction::new_neg(2u8, 5u8)),
("+⅖", Fraction::new (2u8, 5u8)),
("⅗", Fraction::new (3u8, 5u8)),
("-⅗", Fraction::new_neg(3u8, 5u8)),
("+⅗", Fraction::new (3u8, 5u8)),
("⅘", Fraction::new (4u8, 5u8)),
("-⅘", Fraction::new_neg(4u8, 5u8)),
("+⅘", Fraction::new (4u8, 5u8)),
// ("¹⁄₃", Fraction::new(1u8, 3u8)),
];
for (string, frac) in test_vec {
println!("{} ?= {}", string, frac);
assert_eq!(Fraction::unicode_parse(string), Ok(frac));
// println!("{} ?= {}", string, frac);
// assert_eq!(format!("{}", frac.unicode_display()), string);
}
}

#[test]
fn test_fromto_supsub() {
let test_vec = vec![
// super/subscript
("¹/₃", Fraction::new(1u8,3u8)),
("¹²/₂₃", Fraction::new(12u8,23u8)),
];
}

#[test]
fn test_fromto_supsub_mixed() {
let test_vec = vec![
// super/subscript mixed
("1¹/₂", Fraction::new(3u8,2u8)),
];
}

#[test]
fn test_fromto_mixed() {
let test_vec = vec![
("NaN", Fraction::nan()),
("∞", Fraction::infinity()),
Expand All @@ -160,10 +250,6 @@ mod tests {
("1", Fraction::one()),
("-1", -Fraction::one()),
("5", Fraction::from(5)),
// ("nan", Fraction::nan()),
// ("+∞", Fraction::infinity()),
// ("+1", Fraction::one()),
// ("+5", Fraction::from(5)),
("1\u{2064}1⁄2", Fraction::new(3u8, 2u8)),
// ("1⁣1⁄2", Fraction::new(3u8, 2u8)),
("-1\u{2064}1⁄2", Fraction::new_neg(3u8, 2u8)),
Expand All @@ -188,28 +274,21 @@ mod tests {
"1⁤1⁄2BOGUS",
"1⁣1⁄2BOGUS",
"-1⁤1⁄2BOGUS",
"1⁢1⁄2" // uses INVISIBLE_TIMES
"1⁢1⁄2", // uses INVISIBLE_TIMES
];
for s in test_vec {
println!("{}", s);
assert_eq!(
Fraction::unicode_parse(s),
Err(ParseError::ParseIntError)
)
assert_eq!(Fraction::unicode_parse(s), Err(ParseError::ParseIntError))
}
}

#[test]
fn test_fromstr_fraction_ops() {
let test_vec = vec![
"1",
"1/2",
"3/2",
];
let test_vec = vec!["1", "1/2", "3/2"];
for s in test_vec {
let f = Fraction::unicode_parse(s).unwrap();
assert_eq!(f*Fraction::one(), f);
assert_eq!(f+Fraction::zero(), f);
assert_eq!(f * Fraction::one(), f);
assert_eq!(f + Fraction::zero(), f);
}
}
}

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