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|
//! Missing batteries for standard libraries.
use std::{cell::Cell, fmt, time::Instant};
mod macros;
#[inline(always)]
pub fn is_ci() -> bool {
option_env!("CI").is_some()
}
pub trait SepBy: Sized {
/// Returns an `impl fmt::Display`, which joins elements via a separator.
fn sep_by<'a>(self, sep: &'a str) -> SepByBuilder<'a, Self>;
}
impl<I> SepBy for I
where
I: Iterator,
I::Item: fmt::Display,
{
fn sep_by<'a>(self, sep: &'a str) -> SepByBuilder<'a, Self> {
SepByBuilder::new(sep, self)
}
}
pub struct SepByBuilder<'a, I> {
sep: &'a str,
prefix: &'a str,
suffix: &'a str,
iter: Cell<Option<I>>,
}
impl<'a, I> SepByBuilder<'a, I> {
fn new(sep: &'a str, iter: I) -> SepByBuilder<'a, I> {
SepByBuilder { sep, prefix: "", suffix: "", iter: Cell::new(Some(iter)) }
}
pub fn prefix(mut self, prefix: &'a str) -> Self {
self.prefix = prefix;
self
}
pub fn suffix(mut self, suffix: &'a str) -> Self {
self.suffix = suffix;
self
}
/// Set both suffix and prefix.
pub fn surround_with(self, prefix: &'a str, suffix: &'a str) -> Self {
self.prefix(prefix).suffix(suffix)
}
}
impl<I> fmt::Display for SepByBuilder<'_, I>
where
I: Iterator,
I::Item: fmt::Display,
{
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(self.prefix)?;
let mut first = true;
for item in self.iter.take().unwrap() {
if !first {
f.write_str(self.sep)?;
}
first = false;
fmt::Display::fmt(&item, f)?;
}
f.write_str(self.suffix)?;
Ok(())
}
}
#[must_use]
pub fn timeit(label: &'static str) -> impl Drop {
struct Guard {
label: &'static str,
start: Instant,
}
impl Drop for Guard {
fn drop(&mut self) {
eprintln!("{}: {:?}", self.label, self.start.elapsed())
}
}
Guard { label, start: Instant::now() }
}
pub fn to_lower_snake_case(s: &str) -> String {
let mut buf = String::with_capacity(s.len());
let mut prev = false;
for c in s.chars() {
if c.is_ascii_uppercase() && prev {
buf.push('_')
}
prev = true;
buf.push(c.to_ascii_lowercase());
}
buf
}
pub fn replace(buf: &mut String, from: char, to: &str) {
if !buf.contains(from) {
return;
}
// FIXME: do this in place.
*buf = buf.replace(from, to)
}
pub fn split_delim(haystack: &str, delim: char) -> Option<(&str, &str)> {
let idx = haystack.find(delim)?;
Some((&haystack[..idx], &haystack[idx + delim.len_utf8()..]))
}
pub fn trim_indent(mut text: &str) -> String {
if text.starts_with('\n') {
text = &text[1..];
}
let indent = text
.lines()
.filter(|it| !it.trim().is_empty())
.map(|it| it.len() - it.trim_start().len())
.min()
.unwrap_or(0);
lines_with_ends(text)
.map(
|line| {
if line.len() <= indent {
line.trim_start_matches(' ')
} else {
&line[indent..]
}
},
)
.collect()
}
pub fn lines_with_ends(text: &str) -> LinesWithEnds {
LinesWithEnds { text }
}
pub struct LinesWithEnds<'a> {
text: &'a str,
}
impl<'a> Iterator for LinesWithEnds<'a> {
type Item = &'a str;
fn next(&mut self) -> Option<&'a str> {
if self.text.is_empty() {
return None;
}
let idx = self.text.find('\n').map_or(self.text.len(), |it| it + 1);
let (res, next) = self.text.split_at(idx);
self.text = next;
Some(res)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_trim_indent() {
assert_eq!(trim_indent(""), "");
assert_eq!(
trim_indent(
"
hello
world
"
),
"hello\nworld\n"
);
assert_eq!(
trim_indent(
"
hello
world"
),
"hello\nworld"
);
assert_eq!(trim_indent(" hello\n world\n"), "hello\nworld\n");
assert_eq!(
trim_indent(
"
fn main() {
return 92;
}
"
),
"fn main() {\n return 92;\n}\n"
);
}
}
|
