Trait ForeignType

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pub trait ForeignType {
    // Required methods
    fn assignable_from(&self, type_: &Type) -> bool;
    fn assignable_to(&self, type_: &Type) -> bool;
    fn type_ref(&self) -> TokenStream;
    fn decoding_gen(
        &self,
        source: TokenStream,
        output_ref: TokenStream,
        arguments: Vec<TokenStream>,
        is_async: bool,
    ) -> TokenStream;
    fn encoding_gen(
        &self,
        target: TokenStream,
        field_ref: TokenStream,
        arguments: Vec<TokenStream>,
        is_async: bool,
    ) -> TokenStream;
    fn arguments(&self) -> Vec<TypeArgument>;
    fn can_receive_auto(&self) -> Option<ScalarType>;

    // Provided methods
    fn assignable_from_partial(&self, type_: &PartialType) -> bool { ... }
    fn assignable_to_partial(&self, type_: &PartialType) -> bool { ... }
}

Expand description

An encodable and decodable foreign type object Generally these are used to represent complexly encoded types, where there isn’t a notion of smaller internal types

Good examples: Custom encoded integers (i.e. varints) UTF8 strings

Bad examples: GZIP encoded data Encrypted data

Required Methods§

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fn assignable_from(&self, type_: &Type) -> bool

Is this type assignable from this other type? i.e. let X: ThisType = OtherType;

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fn assignable_to(&self, type_: &Type) -> bool

Is this type assignable to this other type? i.e. let X: OtherType = ThisType; Generally identical to ForeignType::assignable_from

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fn type_ref(&self) -> TokenStream

Emits this type as a Rust type

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fn decoding_gen( &self, source: TokenStream, output_ref: TokenStream, arguments: Vec<TokenStream>, is_async: bool, ) -> TokenStream

output code should be a term expression that:

the expression should read its input from an implicit identifier reader as a &mut R where R: Read
can read an arbitrary number of bytes from reader
returns a value of the foreign type

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fn encoding_gen( &self, target: TokenStream, field_ref: TokenStream, arguments: Vec<TokenStream>, is_async: bool, ) -> TokenStream

output code should be a single statement that:

takes an expression field_ref as a reference to a value of the foreign type
the statement should write its output to an implicit identifier writer as a &mut W where W: Write

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fn arguments(&self) -> Vec<TypeArgument>

All arguments that can be passed to this type to describe characteristics (i.e. string length) All optional arguments must come at the end of the list of arguments.

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