Expand description
This crate features utilities for finding the start, end, and range of lines from a byte index. Further also being able to find the next and previous line, from an arbitrary byte index.
This is provided via the trait LineSpanExt
, which is
implemented for str
, and provides the following methods:
Current Line:
find_line_start()
to find the start of the current line.find_line_end()
to find the end of the current line.find_line_range()
to find the start and end current line.
Next Line:
find_next_line_start()
to find the start of the next line.find_next_line_end()
to find the end of the next line.find_next_line_range()
to find the start and end of the next line.
Previous Line:
find_prev_line_start()
to find the start of the previous line.find_prev_line_end()
to find the end of the previous line.find_prev_line_range()
to find both start and end of the previous line.
Iterator:
line_spans()
an iterator overLineSpan
s, i.e.str::lines()
but including the start and end byte indicies (in the form of aRange<usize>
).
Utilities:
str_to_range()
to get the range of a substring in a string.str_to_range_unchecked()
unchecked version ofstr_to_range()
.
LineSpan
and LineSpanIter
The crate includes the LineSpanIter
iterator. It is functionally equivalent to str::lines()
,
with the addition that it includes the ability to get the start and end byte indices of each line.
Additionally, it also includes the ability to get the end including and excluding the line ending (\n
or \r\n
).
An LineSpanIter
can be created by calling line_spans()
,
implemented in the LineSpans
trait.
The crate implements the LineSpans
trait for str
and String
.
Note, LineSpan
implements Deref
to &str
, so in general,
swapping lines()
to line_spans()
would not cause many issues.
use line_span::LineSpanExt;
let text = "foo\nbar\r\nbaz";
for span in text.line_spans() {
println!(
"{:>2?}: {:?} {:?} {:?}",
span.range(),
span.as_str(),
span.as_str_with_ending(),
span.ending_str(),
);
}
This will output the following:
(Manually aligned for better readability)
0.. 3: "foo" "foo\n" "\n"
4.. 7: "bar" "bar\r\n" "\r\n"
9..12: "baz" "baz" ""
Current Line, Previous Line, and Next Line
use line_span::LineSpanExt;
let text = "foo\nbar\r\nbaz";
// ^
let i = 5; // 'a' in "bar"
let curr_range = text.find_line_range(i);
let next_range = text.find_next_line_range(i).unwrap();
let prev_range = text.find_prev_line_range(i).unwrap();
assert_eq!(curr_range, 4..7);
assert_eq!(&text[curr_range], "bar");
assert_eq!(prev_range, 0..3);
assert_eq!(&text[prev_range], "foo");
assert_eq!(next_range, 9..12);
assert_eq!(&text[next_range], "baz");
Range of Substring in String
Use str_to_range
(or str_to_range_unchecked
) to get the
range of a substring in a string.
let string1 = "Foo Bar Baz";
let string2 = "Hello World";
let substring = &string1[4..7]; // "Bar"
// Returns `Some` as `substring` is a part of `string1`
assert_eq!(str_to_range(string1, substring), Some(4..7));
// Returns `None` as `substring` is not a part of `string2`
assert_eq!(str_to_range(string2, substring), None);
Structs
LineSpan
represents a single line. It is possible to get a&str
of the line both including and excluding\n
and\r\n
.- An iterator over
LineSpan
s.
Traits
- Trait implementing utility methods for finding the start, end, and range of lines from a byte index. Further also being able to find the next and previous line, from an arbitrary byte index.
- Trait which implements
line_spans()
to get aLineSpanIter
.
Functions
- Use
LineSpanExt::find_line_end()
instead. - Use
LineSpanExt::find_line_range()
instead. - Use
LineSpanExt::find_line_start()
instead. - Use
LineSpanExt::find_next_line_end()
instead. - Use
LineSpanExt::find_next_line_range()
instead. - Use
LineSpanExt::find_next_line_start()
instead. - Use
LineSpanExt::find_prev_line_end()
instead. - Use
LineSpanExt::find_prev_line_range()
instead. - Use
LineSpanExt::find_prev_line_start()
instead. - Get the start and end (byte index) range (
Range<usize>
), wheresubstring
is located instring
. The returned range is relative tostring
. - Get the start and end (byte index) range (
Range<usize>
), wheresubstring
is located instring
. The returned range is relative tostring
.