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51 lines
1.2 KiB
Rust
51 lines
1.2 KiB
Rust
use crate::error::TapeResult;
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use crate::input_reader::InputReader;
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use std::any::{Any, TypeId};
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use std::future::Future;
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use std::pin::Pin;
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use std::sync::Arc;
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pub type TokenCheckerFn = Arc<
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dyn for<'a> Fn(
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&'a mut InputReader,
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) -> Pin<Box<dyn Future<Output = TapeResult<Option<Token>>> + Send + 'a>>
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+ Send
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+ Sync,
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>;
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pub struct Token {
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inner: Box<dyn Any>,
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}
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impl Token {
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/// Constructs a new token
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pub fn new<A: Any>(inner: A) -> Self {
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Self {
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inner: Box::new(inner),
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}
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}
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/// Tries downcasting the value to a concrete type
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pub fn try_as<T: 'static>(&self) -> Option<&T> {
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self.inner.downcast_ref::<T>()
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}
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pub fn try_into<T: 'static>(self) -> Option<T> {
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match self.inner.downcast() {
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Ok(value) => Some(*value),
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Err(_) => None,
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}
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}
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/// Checks if the inner value is of a given concrete type
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pub fn is<T: 'static>(&self) -> bool {
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self.inner.as_ref().type_id() == TypeId::of::<T>()
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}
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}
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/// Parsed when no other matching token was found for the character
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pub struct UnknownToken(pub char);
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/// End Of File Token
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pub struct EOFToken;
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