Trait Input

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pub trait Input {
Show 32 methods    // Required methods
    fn lookahead(&mut self, count: usize);
    fn buflen(&self) -> usize;
    fn bufmaxlen(&self) -> usize;
    fn raw_read_ch(&mut self) -> char;
    fn raw_read_non_breakz_ch(&mut self) -> Option<char>;
    fn skip(&mut self);
    fn skip_n(&mut self, count: usize);
    fn peek(&self) -> char;
    fn peek_nth(&self, n: usize) -> char;

    // Provided methods
    fn buf_is_empty(&self) -> bool { ... }
    fn look_ch(&mut self) -> char { ... }
    fn next_char_is(&self, c: char) -> bool { ... }
    fn nth_char_is(&self, n: usize, c: char) -> bool { ... }
    fn next_2_are(&self, c1: char, c2: char) -> bool { ... }
    fn next_3_are(&self, c1: char, c2: char, c3: char) -> bool { ... }
    fn next_is_document_indicator(&self) -> bool { ... }
    fn next_is_document_start(&self) -> bool { ... }
    fn next_is_document_end(&self) -> bool { ... }
    fn skip_ws_to_eol(
        &mut self,
        skip_tabs: SkipTabs,
    ) -> (usize, Result<SkipTabs, &'static str>) { ... }
    fn next_can_be_plain_scalar(&self, in_flow: bool) -> bool { ... }
    fn next_is_blank_or_break(&self) -> bool { ... }
    fn next_is_blank_or_breakz(&self) -> bool { ... }
    fn next_is_blank(&self) -> bool { ... }
    fn next_is_break(&self) -> bool { ... }
    fn next_is_breakz(&self) -> bool { ... }
    fn next_is_z(&self) -> bool { ... }
    fn next_is_flow(&self) -> bool { ... }
    fn next_is_digit(&self) -> bool { ... }
    fn next_is_alpha(&self) -> bool { ... }
    fn skip_while_non_breakz(&mut self) -> usize { ... }
    fn skip_while_blank(&mut self) -> usize { ... }
    fn fetch_while_is_alpha(&mut self, out: &mut String) -> usize { ... }
}

Expand description

Interface for a source of characters.

Hiding the input’s implementation behind this trait allows mostly:

For input-specific optimizations (for instance, using str methods instead of manually transferring one char at a time to a buffer).
To return &strs referencing the input string, thus avoiding potentially costly allocations. Should users need an owned version of the data, they can always .to_owned() their YAML object.

Required Methods§

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fn lookahead(&mut self, count: usize)

A hint to the input source that we will need to read count characters.

If the input is exhausted, \0 can be used to pad the last characters and later returned. The characters must not be consumed, but may be placed in an internal buffer.

This method may be a no-op if buffering yields no performance improvement.

Implementers of Input must not load more than count characters into the buffer. The parser tracks how many characters are loaded in the buffer and acts accordingly.

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fn buflen(&self) -> usize

Return the number of buffered characters in self.

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fn bufmaxlen(&self) -> usize

Return the capacity of the buffer in self.

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fn raw_read_ch(&mut self) -> char

Read a character from the input stream and return it directly.

The internal buffer (if any) is bypassed.

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fn raw_read_non_breakz_ch(&mut self) -> Option<char>

Read a non-breakz a character from the input stream and return it directly.

The internal buffer (if any) is bypassed.

If the next character is a breakz, it is either not consumed or placed into the buffer (if any).

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fn skip(&mut self)

Consume the next character.

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fn skip_n(&mut self, count: usize)

Consume the next count character.

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fn peek(&self) -> char

Return the next character, without consuming it.

Users of the Input must make sure that the character has been loaded through a prior call to Input::lookahead. Implementors of Input may assume that a valid call to Input::lookahead has been made beforehand.

§Return

If the input source is not exhausted, returns the next character to be fed into the scanner. Otherwise, returns \0.

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fn peek_nth(&self, n: usize) -> char

Return the n-th character in the buffer, without consuming it.

This function assumes that the n-th character in the input has already been fetched through Input::lookahead.

Provided Methods§

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fn buf_is_empty(&self) -> bool

Return whether the buffer (!= stream) is empty.

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fn look_ch(&mut self) -> char

Look for the next character and return it.

The character is not consumed. Equivalent to calling Input::lookahead and Input::peek.

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fn next_char_is(&self, c: char) -> bool

Return whether the next character in the input source is equal to c.

This function assumes that the next character in the input has already been fetched through Input::lookahead.

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fn nth_char_is(&self, n: usize, c: char) -> bool

Return whether the n-th character in the input source is equal to c.

This function assumes that the n-th character in the input has already been fetched through Input::lookahead.

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fn next_2_are(&self, c1: char, c2: char) -> bool

Return whether the next 2 characters in the input source match the given characters.

This function assumes that the next 2 characters in the input have already been fetched through Input::lookahead.

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fn next_3_are(&self, c1: char, c2: char, c3: char) -> bool

Return whether the next 3 characters in the input source match the given characters.

This function assumes that the next 3 characters in the input have already been fetched through Input::lookahead.

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fn next_is_document_indicator(&self) -> bool

Check whether the next characters correspond to a document indicator.

This function assumes that the next 4 characters in the input has already been fetched through Input::lookahead.

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fn next_is_document_start(&self) -> bool

Check whether the next characters correspond to a start of document.

This function assumes that the next 4 characters in the input has already been fetched through Input::lookahead.

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fn next_is_document_end(&self) -> bool

Check whether the next characters correspond to an end of document.

This function assumes that the next 4 characters in the input has already been fetched through Input::lookahead.

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fn skip_ws_to_eol( &mut self, skip_tabs: SkipTabs, ) -> (usize, Result<SkipTabs, &'static str>)

Skip yaml whitespace at most up to eol. Also skips comments. Advances the input.

§Return

Return a tuple with the number of characters that were consumed and the result of skipping whitespace. The number of characters returned can be used to advance the index and column, since no end-of-line character will be consumed. See SkipTabs For more details on the success variant.

§Errors

Errors if a comment is encountered but it was not preceded by a whitespace. In that event, the first tuple element will contain the number of characters consumed prior to reaching the #.

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fn next_can_be_plain_scalar(&self, in_flow: bool) -> bool

Check whether the next characters may be part of a plain scalar.

This function assumes we are not given a blankz character.

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