Handle exponents in FixedDecimal::from_str() #1265
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| let mut dot_index = no_sign_str_len; | ||
| let mut has_exponent = false; | ||
| let mut dot_index = no_sign_str.len(); | ||
| let mut exponent_index = no_sign_str.len(); |
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question: would Option(index) be a better encapsulation for index and exponent?
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We still use exponent_index even if it's an option, though. I can rename that to exponent_or_end_index
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Isn't expontent.is_none() equivalent of no_sign_str.len() then?
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Yes, I mean that every time we use exponent_index we want to use exponent.unwrap_or(no_sign_str.len()) anyway, so it's not worth it to store the Option
| } | ||
| dot_index = i; | ||
| has_dot = true; | ||
| if i == 0 || i == no_sign_str.len() - 1 { |
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question: it seems like you could get rid of no_sign_str if you just checked the dot: Option(index) after the loop for if it is set to the length of the string.
| if has_exponent && exponent_index == i - 1 { | ||
| continue; | ||
| } else { | ||
| return Err(Error::Syntax); | ||
| } | ||
| } else if *c < b'0' || *c > b'9' { |
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question: is that faster than is_ascii_digit?
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utils/fixed_decimal/src/decimal.rs
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| @@ -570,7 +598,7 @@ impl FromStr for FixedDecimal { | |||
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| // Constructing DecimalFixed.digits | |||
| let mut v: SmallVec<[u8; 8]> = SmallVec::with_capacity(digits_str_len); | |||
| for c in no_sign_str[leftmost_digit..rightmost_digit].iter() { | |||
| for c in no_exponent_str[leftmost_digit..rightmost_digit].iter() { | |||
| if has_exponent { | ||
| let mut pow = 0; | ||
| let mut pos_neg = 1; | ||
| for digit in &no_sign_str[exponent_index + 1..] { |
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Yeah overall that code is existing code and I feel like it's just as complex with the Option, with the complexities shifting around |
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I want to discuss scientific notation from an architecture perspective. Filed #1267. |
Needed for #166