Trait tokenizer_lib::TokenReader [−][src]
pub trait TokenReader<T: PartialEq, TData> {
fn peek(&mut self) -> Option<&Token<T, TData>>;
fn next(&mut self) -> Option<Token<T, TData>>;
fn scan(
&mut self,
cb: impl FnMut(&T, &TData) -> bool
) -> Option<&Token<T, TData>>;
fn expect_next(
&mut self,
expected_type: T
) -> Result<TData, Option<(T, Token<T, TData>)>> { ... }
}
Expand description
A reader over a sequence of tokens
Required methods
Returns a reference to next token but does not advance current position
Runs the closure (cb) over upcoming tokens. Passes the value behind the Token to the closure. Will stop and return a reference to the next Token from when the closure returns true. Returns None if scanning finishes before closure returns true. Does not advance the reader.
Used for lookahead and then branching based on return value during parsing
Provided methods
Tests that next token matches an expected type. Will return error if does not
match. The Ok
value contains the data of the valid token.
Else it will return the Err with the expected token type and the token that did not match