Struct parsel::ast::NotEof

pub struct NotEof;

Verifies that parsing did not yet reach the end of the input (i.e., the end of the parse stream at the current level of nesting). Useful for conditionally parsing an optional production with no other obvious prefix token.

Consumes no tokens when parsed, produces no tokens when printed.

#[derive(PartialEq, Eq, Debug, Parse)]
struct SimpleBlockBody {
    statement: Lit,
    semicolon: Semi,
    expression: Maybe<NotEof, Lit>,
}
type SimpleBlock = Brace<SimpleBlockBody>;

let actual_short: SimpleBlock = "{ 54194; }".parse()?;
let expected_short: SimpleBlock = Brace::new(
    SimpleBlockBody {
        statement: Lit::from(54194_u64),
        semicolon: Semi::default(),
        expression: Maybe::default(),
    },
    Span::call_site(),
);
assert_eq!(actual_short, expected_short);

let actual_long: SimpleBlock = "{ 54194; true }".parse()?;
let expected_long: SimpleBlock = Brace::new(
    SimpleBlockBody {
        statement: Lit::from(54194_u64),
        semicolon: Semi::default(),
        expression: Maybe::from(Lit::from(true)),
    },
    Span::call_site(),
);
assert_eq!(actual_long, expected_long);

// an empty string / token stream should trivially fail to parse as `Eof`
let bad: Result<NotEof> = "".parse();
assert!(bad.is_err());

// an empty string / token stream should trivially fail to parse as `Eof`
let bad_ws_only: Result<NotEof> = " \t\n".parse();
assert!(bad_ws_only.is_err());

Implementations

impl NotEof

pub const fn new() -> Self

Trait Implementations

impl Clone for NotEof

fn clone(&self) -> NotEof

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for NotEof

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for NotEof

fn default() -> NotEof

Returns the “default value” for a type.

impl Display for NotEof

fn fmt(&self, _formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FromStr for NotEof

type Err = Error

The associated error which can be returned from parsing.

fn from_str(string: &str) -> Result<Self>

Parses a string s to return a value of this type.

impl Hash for NotEof

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for NotEof

fn cmp(&self, other: &NotEof) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl Parse for NotEof

fn parse(input: ParseStream<'_>) -> Result<Self>

impl PartialEq for NotEof

fn eq(&self, other: &NotEof) -> bool

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

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for NotEof

fn partial_cmp(&self, other: &NotEof) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl ToTokens for NotEof

fn to_tokens(&self, _tokens: &mut TokenStream)

Write self to the given TokenStream.

fn to_token_stream(&self) -> TokenStream

Convert self directly into a TokenStream object.

fn into_token_stream(self) -> TokenStream

where Self: Sized,

Convert self directly into a TokenStream object.

impl Copy for NotEof

impl Eq for NotEof

impl StructuralPartialEq for NotEof