Struct RStruct

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pub struct RStruct(/* private fields */);

Expand description

A Value pointer to a RStruct struct, Ruby’s internal representation of ‘Structs’.

See the ReprValue and Object traits for additional methods available on this type.

Implementations§

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impl RStruct

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pub fn from_value(val: Value) -> Option<Self>

Return Some(RStruct) if val is a RStruct, None otherwise.

§Examples

use magnus::{Error, RStruct, Ruby};

fn example(ruby: &Ruby) -> Result<(), Error> {
    let struct_class = ruby.define_struct(None, ("foo", "bar"))?;
    ruby.define_global_const("Example", struct_class)?;

    assert!(RStruct::from_value(ruby.eval(r#"Example.new(1, 2)"#)?).is_some());
    assert!(RStruct::from_value(ruby.eval(r#"Object.new"#)?).is_none());

    Ok(())
}

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pub fn get<T>(self, index: usize) -> Result<T, Error>
where T: TryConvert,

Return the value for the member at index, where members are ordered as per the member names when the struct class was defined.

§Examples

use magnus::{prelude::*, Error, RStruct, Ruby};

fn example(ruby: &Ruby) -> Result<(), Error> {
    let struct_class = ruby.define_struct(None, ("foo", "bar"))?;
    let instance = RStruct::from_value(struct_class.new_instance((1, 2))?).unwrap();
    assert_eq!(instance.get::<i64>(0)?, 1);
    assert_eq!(instance.get::<i64>(1)?, 2);

    Ok(())
}

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pub fn aref<T, U>(self, index: T) -> Result<U, Error>
where T: IntoValue, U: TryConvert,

Return the value for the member at index.

index may be an integer, string, or Symbol.

§Examples

use magnus::{prelude::*, Error, RStruct, Ruby};

fn example(ruby: &Ruby) -> Result<(), Error> {
    let struct_class = ruby.define_struct(None, ("foo", "bar", "baz"))?;
    let instance = RStruct::from_value(struct_class.new_instance((1, 2, 3))?).unwrap();
    assert_eq!(instance.aref::<_, i64>(0)?, 1);
    assert_eq!(instance.aref::<_, i64>("bar")?, 2);
    assert_eq!(instance.aref::<_, i64>(ruby.to_symbol("baz"))?, 3);

    Ok(())
}

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pub fn aset<T, U>(self, index: T, val: U) -> Result<(), Error>
where T: IntoValue, U: IntoValue,

Set the value for the member at index.

index may be an integer, string, or Symbol.

§Examples

use magnus::{prelude::*, rb_assert, Error, RStruct, Ruby};

fn example(ruby: &Ruby) -> Result<(), Error> {
    let struct_class = ruby.define_struct(None, ("foo", "bar", "baz"))?;
    let instance = RStruct::from_value(struct_class.new_instance((1, 2, 3))?).unwrap();

    instance.aset(0, 4)?;
    rb_assert!("instance.foo == 4", instance);

    instance.aset("bar", 5)?;
    rb_assert!("instance.bar == 5", instance);

    instance.aset(ruby.to_symbol("baz"), 6)?;
    rb_assert!("instance.baz == 6", instance);

    Ok(())
}

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pub fn size(self) -> usize

Returns the count of members this struct has.

§Examples

use magnus::{prelude::*, Error, RStruct, Ruby};

fn example(ruby: &Ruby) -> Result<(), Error> {
    let struct_class = ruby.define_struct(None, ("foo", "bar", "baz"))?;
    let instance = RStruct::from_value(struct_class.new_instance(())?).unwrap();

    assert_eq!(instance.size(), 3);

    Ok(())
}

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pub fn members(self) -> Result<Vec<Cow<'static, str>>, Error>

Returns the member names for this struct.

§Examples

use magnus::{prelude::*, Error, RStruct, Ruby};

fn example(ruby: &Ruby) -> Result<(), Error> {
    let struct_class = ruby.define_struct(None, ("foo", "bar", "baz"))?;
    let instance = RStruct::from_value(struct_class.new_instance(())?).unwrap();

    assert_eq!(instance.members()?, &["foo", "bar", "baz"]);

    Ok(())
}

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pub fn getmember<T, U>(self, id: T) -> Result<U, Error>
where T: IntoId, U: TryConvert,

Return the value for the member named id.

§Examples

use magnus::{prelude::*, Error, RStruct, Ruby};

fn example(ruby: &Ruby) -> Result<(), Error> {
    let struct_class = ruby.define_struct(None, ("foo", "bar"))?;
    let instance = RStruct::from_value(struct_class.new_instance((1, 2))?).unwrap();
    assert_eq!(instance.getmember::<_, i64>("foo")?, 1);
    assert_eq!(instance.getmember::<_, i64>("bar")?, 2);

    Ok(())
}