[−][src]Struct uwl::StringStream
A stream of chars. Handles both ASCII and Unicode.
Note
This stream returns chars as &str
s. In instances like take_while
, the &str
refers to actual multi-char substrings (e.g "foo").
Fields
src: &'a str
The source this stream operates on.
Methods
impl<'a> StringStream<'a>
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pub fn new(src: &'a str) -> Self
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Create a new stream from a source.
pub fn current(&self) -> Option<&'a str>
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Fetch the current char.
Example
use uwl::StringStream; let stream = StringStream::new("hello"); assert_eq!(stream.current(), Some("h"));
pub fn next(&mut self) -> Option<&'a str>
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Advance to the next char
Example
use uwl::StringStream; let mut stream = StringStream::new("hello"); assert_eq!(stream.current(), Some("h")); stream.next(); assert_eq!(stream.current(), Some("e"));
pub fn advance(&mut self, much: usize) -> Option<&'a str>
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Advance by x chars.
Example
use uwl::StringStream; let mut stream = StringStream::new("hello world"); assert_eq!(stream.advance(5), Some("hello")); stream.next(); assert_eq!(stream.advance(5), Some("world")); assert!(stream.at_end());
pub fn eat(&mut self, m: &str) -> bool
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Advance if the leading string matches to the expected input.
Returns true
on succession, false
on failure.
Example
use uwl::StringStream; let mut stream = StringStream::new("hello world"); assert!(stream.eat("hello")); assert!(!stream.eat("not a space")); assert!(stream.eat(" ")); assert_eq!(stream.rest(), "world");
pub fn peek(&self, ahead: usize) -> Option<&'a str>
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Lookahead by x chars. Returns the char it landed on.
Example
use uwl::StringStream; let mut stream = StringStream::new("hello"); assert_eq!(stream.current(), Some("h")); assert_eq!(stream.peek(1), Some("e")); assert_eq!(stream.current(), Some("h")); assert_eq!(stream.peek(2), Some("l")); assert_eq!(stream.current(), Some("h"));
pub fn peek_for(&self, ahead: usize) -> &'a str
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Lookahead by x chars. Returns a substring up to the end it landed on.
Example
use uwl::StringStream; let mut stream = StringStream::new("hello world"); assert_eq!(stream.current(), Some("h")); assert_eq!(stream.peek_for(5), "hello"); for _ in 0..5 { stream.next(); } assert_eq!(stream.next(), Some(" ")); assert_eq!(stream.peek_for(5), "world"); assert_eq!(stream.next(), Some("w")); assert_eq!(stream.next(), Some("o")); assert_eq!(stream.next(), Some("r")); assert_eq!(stream.next(), Some("l")); assert_eq!(stream.next(), Some("d"));
pub fn peek_str(&self, ahead: usize) -> &'a str
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renamed to peek_for
Lookahead by x chars. Returns a substring up to the end it landed on.
Deprecated
Use peek_for
instead.
pub fn take_while(&mut self, f: impl Fn(&str) -> bool) -> &'a str
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Consume while true.
Example
use uwl::StringStream; // Import a few utility methods (for `is_alphabetic`) use uwl::StrExt; let mut stream = StringStream::new("hello"); assert_eq!(stream.current(), Some("h")); assert_eq!(stream.take_while(|s| s.is_alphabetic()), "hello"); assert_eq!(stream.current(), None);
pub fn take_until(&mut self, f: impl Fn(&str) -> bool) -> &'a str
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Consume until true.
Example
use uwl::StringStream; let mut stream = StringStream::new("hello!"); assert_eq!(stream.current(), Some("h")); assert_eq!(stream.take_until(|s| s == "!"), "hello"); assert_eq!(stream.current(), Some("!"));
pub fn parse<'b>(&mut self, fmt: &'b str) -> Result<&'a str, &'b str>
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Slice a portion from the stream by using rules defined by the formatting string
{}
=> the portion to return(x)
=> optional text x that may be present, ignored- letters/numbers => text to expect
To espace {
or (
, use them twice. For example, ((
/{{
.
This is not necessary for }
or )
.
Whitespace between {
and }
is skipped.
If parsing does not succeed, this won't advance.
On Err
, the expected string, or "parse failed", are returned.
Examples
Get anything between html h1
tags
use uwl::StringStream; let mut stream = StringStream::new("<h1>hello world!</h1>"); assert_eq!(stream.parse("<h1>{}</h1>"), Ok("hello world!"));
Parse html tags
use uwl::StringStream; let mut stream = StringStream::new("<h2></h2>"); // the opening tag - <h2> assert_eq!(stream.parse("<(/){}>"), Ok("h2")); // the closing tag - </h2> assert_eq!(stream.parse("<(/){}>"), Ok("h2"));
pub fn rest(&self) -> &'a str
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Returns the remainder (after the offset).
Example
use uwl::StringStream; let mut stream = StringStream::new("foo bar"); assert_eq!(stream.take_until(|s| s == " "), "foo"); assert_eq!(stream.next(), Some(" ")); assert_eq!(stream.rest(), "bar");
pub fn at_end(&self) -> bool
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Determines the end of the input.
Example
use uwl::StringStream; let mut stream = StringStream::new("a"); assert!(!stream.at_end()); stream.next(); assert!(stream.at_end()); assert_eq!(stream.current(), None);
pub fn offset(&self) -> usize
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The "offset"; the start of the current char.
Example
use uwl::StringStream; let mut stream = StringStream::new("a 🍆"); assert_eq!(stream.offset(), 0); stream.next(); assert_eq!(stream.offset(), 1); stream.next(); assert_eq!(stream.offset(), 2); stream.next(); assert_eq!(stream.offset(), 6);
pub fn set(&mut self, pos: usize)
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Set the offset. Panics if the offset is in the middle of a unicode character, or exceeds the length of the input.
pub unsafe fn set_unchecked(&mut self, pos: usize)
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Set the offset without any checks.
Trait Implementations
impl<'a> Debug for StringStream<'a>
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impl<'a> Clone for StringStream<'a>
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fn clone(&self) -> StringStream<'a>
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fn clone_from(&mut self, source: &Self)
1.0.0[src]
Performs copy-assignment from source
. Read more
Auto Trait Implementations
impl<'a> Send for StringStream<'a>
impl<'a> Sync for StringStream<'a>
Blanket Implementations
impl<T> From for T
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impl<T, U> TryFrom for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T, U> Into for T where
U: From<T>,
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U: From<T>,
impl<T> Borrow for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,