Trait nom::lib::std::ops::Index1.0.0[−][src]

#[lang = "index"]

pub trait Index<Idx> where
    Idx: ?Sized, {
    type Output: ?Sized;
    fn index(&self, index: Idx) -> &Self::Output;
}

Used for indexing operations (container[index]) in immutable contexts.

container[index] is actually syntactic sugar for *container.index(index), but only when used as an immutable value. If a mutable value is requested, IndexMut is used instead. This allows nice things such as let value = v[index] if the type of value implements Copy.

Examples

The following example implements Index on a read-only NucleotideCount container, enabling individual counts to be retrieved with index syntax.

use std::ops::Index;

enum Nucleotide {
    A,
    C,
    G,
    T,
}

struct NucleotideCount {
    a: usize,
    c: usize,
    g: usize,
    t: usize,
}

impl Index<Nucleotide> for NucleotideCount {
    type Output = usize;

    fn index(&self, nucleotide: Nucleotide) -> &usize {
        match nucleotide {
            Nucleotide::A => &self.a,
            Nucleotide::C => &self.c,
            Nucleotide::G => &self.g,
            Nucleotide::T => &self.t,
        }
    }
}

let nucleotide_count = NucleotideCount {a: 14, c: 9, g: 10, t: 12};
assert_eq!(nucleotide_count[Nucleotide::A], 14);
assert_eq!(nucleotide_count[Nucleotide::C], 9);
assert_eq!(nucleotide_count[Nucleotide::G], 10);
assert_eq!(nucleotide_count[Nucleotide::T], 12);

Associated Types

The returned type after indexing.

Required Methods

Performs the indexing (container[index]) operation.

Implementations on Foreign Types

impl Index<RangeFull> for CString
[src]

impl Index<RangeFull> for OsString
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impl Index<Range<usize>> for str
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Implements substring slicing with syntax &self[begin .. end].

Returns a slice of the given string from the byte range [begin..end).

This operation is O(1).

Panics

Panics if begin or end does not point to the starting byte offset of a character (as defined by is_char_boundary). Requires that begin <= end and end <= len where len is the length of the string.

Examples

let s = "Löwe 老虎 Léopard";
assert_eq!(&s[0 .. 1], "L");

assert_eq!(&s[1 .. 9], "öwe 老");

// these will panic:
// byte 2 lies within `ö`:
// &s[2 ..3];

// byte 8 lies within `老`
// &s[1 .. 8];

// byte 100 is outside the string
// &s[3 .. 100];

impl Index<RangeFrom<usize>> for str
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Implements substring slicing with syntax &self[begin ..].

Returns a slice of the string from byte offset begin to the end of the string.

Equivalent to &self[begin .. len].

impl Index<RangeToInclusive<usize>> for str
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impl Index<RangeFull> for str
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Implements substring slicing with syntax &self[..].

Returns a slice of the whole string. This operation can never panic.

Equivalent to &self[0 .. len].

impl Index<RangeTo<usize>> for str
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Implements substring slicing with syntax &self[.. end].

Returns a slice of the string from the beginning to byte offset end.

Equivalent to &self[0 .. end].

impl<T, I> Index<I> for [T] where
    I: SliceIndex<[T]>, 
[src]

impl Index<RangeInclusive<usize>> for str
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impl<'t, 'i> Index<&'i str> for Captures<'t>
[src]

Get a group by name.

't is the lifetime of the matched text and 'i is the lifetime of the group name (the index).

The text can't outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can't outlive it); to do that, use name instead.

Panics

If there is no group named by the given value.

impl<'t> Index<usize> for Captures<'t>
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Get a group by index.

't is the lifetime of the matched text.

The text can't outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can't outlive it); to do that, use get() instead.

Panics

If there is no group at the given index.

ⓘImportant traits for &'a [u8]

impl<'t> Index<usize> for Captures<'t>
[src]

Get a group by index.

't is the lifetime of the matched text.

The text can't outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can't outlive it); to do that, use get() instead.

Panics

If there is no group at the given index.

impl<'t, 'i> Index<&'i str> for Captures<'t>
[src]

Get a group by name.

't is the lifetime of the matched text and 'i is the lifetime of the group name (the index).

The text can't outlive the Captures object if this method is used, because of how Index is defined (normally a[i] is part of a and can't outlive it); to do that, use name instead.

Panics

If there is no group named by the given value.

ⓘImportant traits for &'a [u8]

Implementors