bf9f58e11b
* Add docs for mdBook specific include feature. Also: * Fix bug in take_lines taking `end`-many lines instead of `end-start` many. * Handle special case `include:number` as including a single line. * Start counting lines at 1 and not 0. * Merge mdBook and rust specific features into one chapter.
73 lines
1.8 KiB
Rust
73 lines
1.8 KiB
Rust
use std::ops::{Range, RangeFrom, RangeFull, RangeTo};
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use itertools::Itertools;
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// This trait is already contained in the standard lib, however it is unstable.
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// TODO: Remove when the `collections_range` feature stabilises
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// (https://github.com/rust-lang/rust/issues/30877)
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pub trait RangeArgument<T: ?Sized> {
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fn start(&self) -> Option<&T>;
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fn end(&self) -> Option<&T>;
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}
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impl<T: ?Sized> RangeArgument<T> for RangeFull {
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fn start(&self) -> Option<&T> {
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None
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}
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fn end(&self) -> Option<&T> {
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None
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}
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}
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impl<T> RangeArgument<T> for RangeFrom<T> {
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fn start(&self) -> Option<&T> {
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Some(&self.start)
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}
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fn end(&self) -> Option<&T> {
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None
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}
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}
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impl<T> RangeArgument<T> for RangeTo<T> {
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fn start(&self) -> Option<&T> {
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None
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}
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fn end(&self) -> Option<&T> {
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Some(&self.end)
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}
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}
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impl<T> RangeArgument<T> for Range<T> {
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fn start(&self) -> Option<&T> {
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Some(&self.start)
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}
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fn end(&self) -> Option<&T> {
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Some(&self.end)
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}
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}
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/// Take a range of lines from a string.
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pub fn take_lines<R: RangeArgument<usize>>(s: &str, range: R) -> String {
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let start = *range.start().unwrap_or(&0);
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let mut lines = s.lines().skip(start);
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match range.end() {
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Some(&end) => lines.take(end.checked_sub(start).unwrap_or(0)).join("\n"),
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None => lines.join("\n"),
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}
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}
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#[cfg(test)]
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mod tests {
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use super::take_lines;
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#[test]
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fn take_lines_test() {
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let s = "Lorem\nipsum\ndolor\nsit\namet";
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assert_eq!(take_lines(s, 1..3), "ipsum\ndolor");
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assert_eq!(take_lines(s, 3..), "sit\namet");
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assert_eq!(take_lines(s, ..3), "Lorem\nipsum\ndolor");
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assert_eq!(take_lines(s, ..), s);
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// corner cases
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assert_eq!(take_lines(s, 4..3), "");
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assert_eq!(take_lines(s, ..100), s);
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}
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}
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