Struct nom_locate::LocatedSpan[−][src]

pub struct LocatedSpan<T, X = ()> {
    pub extra: X,
    // some fields omitted
}
Expand description

A LocatedSpan is a set of meta information about the location of a token, including extra information.

The LocatedSpan structure can be used as an input of the nom parsers. It implements all the necessary traits for LocatedSpan<&str,X> and LocatedSpan<&[u8],X>

Fields

extra: X

Extra information that can be embedded by the user. Example: the parsed file name

Implementations

Create a span for a particular input with default offset and line values and empty extra data. You can compute the column through the get_column or get_utf8_column methods.

offset starts at 0, line starts at 1, and column starts at 1.

Do not use this constructor in parser functions; nom and nom_locate assume span offsets are relative to the beginning of the same input. In these cases, you probably want to use the nom::traits::Slice trait instead.

Example of use

use nom_locate::LocatedSpan;

let span = LocatedSpan::new(b"foobar");

assert_eq!(span.location_offset(), 0);
assert_eq!(span.location_line(),   1);
assert_eq!(span.get_column(),      1);
assert_eq!(span.fragment(),        &&b"foobar"[..]);

Create a span for a particular input with default offset and line values. You can compute the column through the get_column or get_utf8_column methods.

offset starts at 0, line starts at 1, and column starts at 1.

Do not use this constructor in parser functions; nom and nom_locate assume span offsets are relative to the beginning of the same input. In these cases, you probably want to use the nom::traits::Slice trait instead.

Example of use

use nom_locate::LocatedSpan;

let span = LocatedSpan::new_extra(b"foobar", "extra");

assert_eq!(span.location_offset(), 0);
assert_eq!(span.location_line(),   1);
assert_eq!(span.get_column(),      1);
assert_eq!(span.fragment(),        &&b"foobar"[..]);
assert_eq!(span.extra,             "extra");

Similar to new_extra, but allows overriding offset and line. This is unsafe, because giving an offset too large may result in undefined behavior, as some methods move back along the fragment assuming any negative index within the offset is valid.

The offset represents the position of the fragment relatively to the input of the parser. It starts at offset 0.

The line number of the fragment relatively to the input of the parser. It starts at line 1.

The fragment that is spanned. The fragment represents a part of the input of the parser.

Return the line that contains this LocatedSpan.

The get_column and get_utf8_column functions returns indexes that corresponds to the line returned by this function.

Note that if this LocatedSpan ends before the end of the original data, the result of calling get_line_beginning() will not include any data from after the LocatedSpan.

let program = LocatedSpan::new(
    "Hello World!\
    \nThis is a multi-line input\
    \nthat ends after this line.\n");
let multi = program.find_substring("multi").unwrap();

assert_eq!(
    program.slice(multi..).get_line_beginning(),
    "This is a multi-line input".as_bytes(),
);

Return the column index, assuming 1 byte = 1 column.

Use it for ascii text, or use get_utf8_column for UTF8.

Example of use


let span = LocatedSpan::new("foobar");

assert_eq!(span.slice(3..).get_column(), 4);

Return the column index for UTF8 text. Return value is unspecified for non-utf8 text.

This version uses bytecount’s hyper algorithm to count characters. This is much faster for long lines, but is non-negligibly slower for short slices (below around 100 bytes). This is also sped up significantly more depending on architecture and enabling the simd feature gates. If you expect primarily short lines, you may get a noticeable speedup in parsing by using naive_get_utf8_column instead. Benchmark your specific use case!

Example of use


let span = LocatedSpan::new("メカジキ");
let indexOf3dKanji = span.find_substring("ジ").unwrap();

assert_eq!(span.slice(indexOf3dKanji..).get_column(), 7);
assert_eq!(span.slice(indexOf3dKanji..).get_utf8_column(), 3);

Return the column index for UTF8 text. Return value is unspecified for non-utf8 text.

A simpler implementation of get_utf8_column that may be faster on shorter lines. If benchmarking shows that this is faster, you can use it instead of get_utf8_column. Prefer defaulting to get_utf8_column unless this legitimately is a performance bottleneck.

Example of use


let span = LocatedSpan::new("メカジキ");
let indexOf3dKanji = span.find_substring("ジ").unwrap();

assert_eq!(span.slice(indexOf3dKanji..).get_column(), 7);
assert_eq!(span.slice(indexOf3dKanji..).naive_get_utf8_column(), 3);

Trait Implementations

Casts the input type to a byte slice

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Compares self to another value for equality

Compares self to another value for equality independently of the case. Read more

Formats the value using the given formatter. Read more

The resulting type after dereferencing.

Dereferences the value.

Formats the value using the given formatter. Read more

The current input type is a sequence of that Item type. Read more

The type that will be produced

Create a new Extend of the correct type

Accumulate the input into an accumulator

Returns the byte position of the substring if it is found

Returns true if self contains the token

Performs the conversion.

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

The current input type is a sequence of that Item type. Read more

An iterator over the input type, producing the item and its position for use with Slice. If we’re iterating over &str, the position corresponds to the byte index of the character Read more

An iterator over the input type, producing the item

Returns an iterator over the elements and their byte offsets

Returns an iterator over the elements

Finds the byte position of the element

Get the byte offset from the element’s position in the stream

Calculates the input length, as indicated by its name, and the name of the trait itself Read more

Returns a slice of count bytes. panics if count > length

Split the stream at the count byte offset. panics if count > length

The current input type is a sequence of that Item type. Read more

Looks for the first element of the input type for which the condition returns true, and returns the input up to this position. Read more

Looks for the first element of the input type for which the condition returns true, and returns the input up to this position. Read more

Looks for the first element of the input type for which the condition returns true and returns the input up to this position. Read more

Looks for the first element of the input type for which the condition returns true and returns the input up to this position. Read more

Offset between the first byte of self and the first byte of the argument

Succeeds if parse() succeeded. The byte slice implementation will first convert it to a &str, then apply the parse() function Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

Slices self according to the range argument

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

Converts the given value to a String. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.