bdfe1b9fb0
It currently only inserts separators into `usize`s, because that's all that has been needed so far. `-Zmacro-stats` will need `isize` and `f64` handling, so this commit adds that.
37 lines
1.1 KiB
Rust
37 lines
1.1 KiB
Rust
//! This is a bare-bones alternative to the `thousands` crate on crates.io, for
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//! printing large numbers in a readable fashion.
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#[cfg(test)]
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mod tests;
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fn format_with_underscores(mut s: String) -> String {
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// Ignore a leading '-'.
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let start = if s.starts_with('-') { 1 } else { 0 };
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// Stop after the first non-digit, e.g. '.' or 'e' for floats.
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let non_digit = s[start..].find(|c: char| !c.is_digit(10));
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let end = if let Some(non_digit) = non_digit { start + non_digit } else { s.len() };
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// Insert underscores within `start..end`.
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let mut i = end;
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while i > start + 3 {
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i -= 3;
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s.insert(i, '_');
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}
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s
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}
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/// Print a `usize` with underscore separators.
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pub fn usize_with_underscores(n: usize) -> String {
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format_with_underscores(format!("{n}"))
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}
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/// Print an `isize` with underscore separators.
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pub fn isize_with_underscores(n: isize) -> String {
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format_with_underscores(format!("{n}"))
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}
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/// Print an `f64` with precision 1 (one decimal place) and underscore separators.
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pub fn f64p1_with_underscores(n: f64) -> String {
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format_with_underscores(format!("{n:.1}"))
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}
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