Struct Fragment

pub struct Fragment {
    pub source: SourceRef,
    pub range: Range<usize>,
}

Available on crate feature source-tracking only.

A fragment of source code.

This can be part of (or all of) a Source.

Fields

source: SourceRef

The Source that this fragment is in.

range: Range<usize>

Fragments are represented using byte ranges in the Source referenced by Fragment::source.

This Fragment is considered invalid if this range is out of order or either end of it is not on a char boundary in source according to str::is_char_boundary.

Implementations

impl Fragment

pub fn is_valid(&self) -> bool

Check that this Fragment is valid, and references a real existing (though possibly empty) part of the Fragment::source.

pub fn as_str(&self) -> &str

Get the str represented by this Fragment.

Panics

• This will panic in the unlikely event that Fragment::range is out of bounds or lands between char boundaries for Fragment::source.

pub const fn len(&self) -> usize

Get the length (in bytes) of this Fragment. Does not check this Fragment for validity.

pub const fn is_empty(&self) -> bool

Check if this fragment has a Fragment::len == 0. Does not check this Fragment for validity.

pub fn is_empty_at_end_of_source(&self) -> bool

Check if this fragment is empty at the end of it’s source.

Uses debug_assert to check for validity.

pub fn contains(&self, other: &Self) -> bool

Return true if this Fragment entirely contains another Fragment and they’re from the same Source by Source::id.

If other is empty, it can still be considered to be contained in this Fragment if its Fragment::range is entirely within self’s Fragment::range (basically whether the location of the empty fragment is in this one).

pub fn offset_from(&self, origin: &Self) -> usize

Get the number of bytes between the beginning of origin and the beginning of self.

Panics:

• Panics if self is not a Fragment within origin according to Fragment::contains.

pub fn chars(&self) -> Chars<'_>

Get a Chars Iterator over the characters in this Fragment.

pub fn trimmed(self) -> Self

Get a sub-fragment of this fragment (see Fragment::contains) with the whitespace at either end trimmed off. This will return the fragment unchanged if it is empty.

This calls Fragment::trim_start and then Fragment::trim_end internally and should match the behavior of str::trim.

If this returns an empty Fragment it will be at the end of the parent Fragment.

pub fn trim_end(self) -> Self

Get a sub-fragment of this fragment (see Fragment::contains) with the whitespace trimmed off the end. This will return it unchanged if empty.

See str::trim_end for exact behaviors.

pub fn trim_start(self) -> Self

Get a sub-fragment of this fragment (see Fragment::contains) with the whitespace trimmed off the start. This will return it unchanged if empty.

See str::trim_start for exact behaviors.

pub fn split_at(&self, bytes_from_start: usize) -> (Self, Self)

Split this Fragment into two sub-Fragments, the left containing the first bytes_from_start bytes, and the right containing the rest.

Panics

• This will panic if the provided bytes_from_start does not land on a unicode character boundary or is larger than the length of this fragment according to str::is_char_boundary.

pub fn split_at_unchecked(&self, bytes_from_start: usize) -> (Self, Self)

This is the same as Fragment::split_at except it does not check that the created fragments are valid or that either can call Fragment::as_str without panicking. Use with caution.

Note that this is not technically unsafe, since all bugs that may emerge from abuse/misuse here are logic bugs (not memory or concurrency bugs).

pub fn advance_by(&mut self, bytes: usize)

Move the start of this Fragment forward by a given number of bytes.

Panics

• Panics if the advancing by bytes would create an invalid Fragment.

pub fn advance_by_unchecked(&mut self, bytes: usize)

This is the same as Fragment::advance_by except without the bounds checking. Use carefully or the updated Fragment will be invalid.

pub fn retain(&mut self, bytes: usize)

Retain up to bytes bytes of this Fragment.

Panics

• Panics if the updated Fragment would be invalid.

pub fn retain_unchecked(&mut self, bytes: usize)

This is the same as Fragment::retain except without the bounds checking. Use carefully or the updated Fragment will be invalid.

pub fn line_indices(&self) -> Range<usize>

Get a Range of line indices (0-indexed, see Source::get_line) that this fragment overlaps.

pub fn starts_on_line(&self) -> usize

Get the line number (not index) that this line starts on.

This re-calculates Fragment::line_indices, which may be expensive on very large files, so use with care.

pub fn starting_col_index(&self) -> usize

Get the number of bytes between the start of the line that this Fragment starts on and the start of this Fragment

pub fn cover(lhs: Fragment, rhs: Fragment) -> Fragment

Compute the “cover” over two Fragments – that is, the Fragment containing both of them and all the source code in between.

Panics

• If the Fragments are from different sources.

Trait Implementations

impl Clone for Fragment

fn clone(&self) -> Fragment

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Fragment

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Fragment

fn fmt(&self, __derive_more_f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Fragment

fn eq(&self, other: &Self) -> bool

Fragment equality is based on referencing the same Source using Arc::ptr_eq and having the same Fragment::range.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Fragment