Struct magnus::Binding

source · [−]

#[repr(transparent)]
pub struct Binding(_);

Expand description

A Value known to be an instance of Binding.

All Value methods should be available on this type through Deref, but some may be missed by this documentation.

Implementations

source

impl Binding

source

pub fn new() -> Self

👎 Deprecated since 0.2.0:

this will no longer function as of Ruby 3.2

Create a new Binding from the current Ruby execution context.

Examples

use magnus::Binding;

let binding = Binding::new();

source

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

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

source

pub fn eval<T, U>(&self, s: T) -> Result<U, Error> where
T: Into<RString>,
U: TryConvert,

Evaluate a string of Ruby code within the binding’s context.

Examples

use magnus::{eval, Binding};

let binding = eval::<Binding>("binding").unwrap();
assert_eq!(binding.eval::<_, i64>("1 + 2").unwrap(), 3);

source

pub fn local_variable_get<N, T>(&self, name: N) -> Result<T, Error> where
N: Into<Symbol>,
T: TryConvert,

Get the named local variable from the binding.

Returns Ok(T) if the method returns without error and the return value converts to a T, or returns Err if the local variable does not exist or the conversion fails.

Examples

use magnus::{eval, Binding, Value};

let binding = eval::<Binding>("binding").unwrap();
binding.local_variable_set("a", 1);
assert_eq!(binding.local_variable_get::<_, i64>("a").unwrap(), 1);
assert!(binding.local_variable_get::<_, Value>("b").is_err());

source

pub fn local_variable_set<N, T>(&self, name: N, val: T) where
N: Into<Symbol>,
T: Into<Value>,

Set the named local variable in the binding.

Examples

use magnus::{eval, Binding};

let binding = eval::<Binding>("binding").unwrap();
binding.local_variable_set("a", 1);
assert_eq!(binding.local_variable_get::<_, i64>("a").unwrap(), 1);

Methods from Deref<Target = Value>

source

pub unsafe fn to_s(&self) -> Result<Cow<'_, str>, Error>

Convert self to a Rust string.

Safety

This may return a direct view of memory owned and managed by Ruby. Ruby may modify or free the memory backing the returned str, the caller must ensure this does not happen.

This can be used safely by immediately calling into_owned on the return value.

Examples

use magnus::{eval, QTRUE};

let value = QTRUE;
// safe as we neve give Ruby a chance to free the string.
let s = unsafe { value.to_s() }.unwrap().into_owned();
assert_eq!(s, "true");

source

pub unsafe fn classname(&self) -> Cow<'_, str>

Return the name of self’s class.

Safety

Ruby may modify or free the memory backing the returned str, the caller must ensure this does not happen.

This can be used safely by immediately calling into_owned on the return value.

Examples

use magnus::{eval, RHash};

let value = RHash::new();
// safe as we neve give Ruby a chance to free the string.
let s = unsafe { value.classname() }.into_owned();
assert_eq!(s, "Hash");

source

pub fn try_convert<T>(&self) -> Result<T, Error> where
T: TryConvert,

Convert self to the Rust type T.

See the types that TryConvert is implemented on for what this method can convert to.

Examples

use magnus::{eval, Value};

assert_eq!(eval::<Value>("42").unwrap().try_convert::<i64>().unwrap(), 42);
assert_eq!(eval::<Value>("1.23").unwrap().try_convert::<i64>().unwrap(), 1);
assert_eq!(eval::<Value>("1").unwrap().try_convert::<f64>().unwrap(), 1.0);
assert_eq!(eval::<Value>("nil").unwrap().try_convert::<Option<i64>>().unwrap(), None);
assert_eq!(eval::<Value>("42").unwrap().try_convert::<Option<i64>>().unwrap(), Some(42));