Struct PredicateCmp 

pub struct PredicateCmp<A, B, Same = Enable, Different = Disable>(/* private fields */)
where
    A: PredicateOp,
    B: PredicateOp,
    Same: PredicateOp,
    Different: PredicateOp;

Predicate that compares type A with type B at runtime.

Acts like Same when A == B (=Enable), and Differentwhen A != B (=Disable). This enables distinguishing between different predicate flags at compile time through runtime type checks (which are usually optimized away by the compiler).

Examples

use unsynn::*;
//use unsynn::predicates::*;

unsynn! {
    predicatetrait Context;
    predicateflag InExpr for Context;
    predicateflag InStmt for Context;

    // Only accepts InExpr, rejects InStmt
    struct OnlyInExpr<C: Context> {
        _guard: PredicateCmp<C, InExpr>,
        content: Ident,
    }

    // Accepts InExpr but NOT InStmt
    struct ExprButNotStmt<C: Context> {
        _guard: AllOf<PredicateCmp<C, InExpr>, Not<PredicateCmp<C, InStmt>>>,
        content: Ident,
    }
}

Implementations

impl<A, B, Same, Different> PredicateCmp<A, B, Same, Different>

where A: PredicateOp, B: PredicateOp, Same: PredicateOp, Different: PredicateOp,

pub const fn new() -> PredicateCmp<A, B, Same, Different>

Create a new PredicateCmp instance.

This is primarily useful for testing or when you need to manually construct the predicate.

Trait Implementations

impl<A, B, Same, Different> Clone for PredicateCmp<A, B, Same, Different>

where A: PredicateOp, B: PredicateOp, Same: PredicateOp, Different: PredicateOp,

fn clone(&self) -> PredicateCmp<A, B, Same, Different>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<A, B, Same, Different> Debug for PredicateCmp<A, B, Same, Different>

where A: Debug + PredicateOp, B: Debug + PredicateOp, Same: Debug + PredicateOp, Different: Debug + PredicateOp,

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

Formats the value using the given formatter.

impl<A, B, Same, Different> Default for PredicateCmp<A, B, Same, Different>

where A: PredicateOp, B: PredicateOp, Same: PredicateOp, Different: PredicateOp,

fn default() -> PredicateCmp<A, B, Same, Different>

Returns the “default value” for a type.

impl<A, B, Same, Different> Parser for PredicateCmp<A, B, Same, Different>

where A: PredicateOp, B: PredicateOp, Same: PredicateOp, Different: PredicateOp,

fn parser( tokens: &mut TokenIter, ) -> Result<PredicateCmp<A, B, Same, Different>, Error>

The actual parsing function that must be implemented. This mutates the tokens iterator directly. It should not be called from user code except for implementing parsers itself and then only when the rules below are followed.

impl<A, B, Same, Different> ToTokens for PredicateCmp<A, B, Same, Different>

where A: PredicateOp, B: PredicateOp, Same: PredicateOp, Different: PredicateOp,

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

Write &self to the given TokenStream.

fn to_token_iter(&self) -> TokenIter

Convert &self into a TokenIter object.

fn into_token_iter(self) -> TokenIter

where Self: Sized,

Convert self into a TokenIter object.

fn to_token_stream(&self) -> TokenStream

Convert &self into a TokenStream object.

fn into_token_stream(self) -> TokenStream

where Self: Sized,

Convert self into a TokenStream object.

fn tokens_to_string(&self) -> String

Convert &self into a String object. This is mostly used in the test suite to compare the outputs. When the input is a &str then this parses it and returns a normalized String.

impl<A, B, Same, Different> Copy for PredicateCmp<A, B, Same, Different>

where A: PredicateOp, B: PredicateOp, Same: PredicateOp, Different: PredicateOp,

impl<A, B, Same, Different> PredicateOp for PredicateCmp<A, B, Same, Different>

where A: PredicateOp, B: PredicateOp, Same: PredicateOp, Different: PredicateOp,