Struct magnus::r_string::FString

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

FString contains an RString known to be interned.

Interned strings won’t be garbage collected or modified, so should be safe to store on the heap or hold a &str refrence to. FString provides a way to encode this property into the type system, and provides safe methods to access the string as a &str or slice.

Implementations

impl FString

pub fn as_r_string(self) -> RString

Returns the interned string as a RString.

pub fn as_slice(self) -> &'static [u8]

Returns the interned string as a slice of bytes.

Examples

use magnus::{eval, RString};

let s: RString = eval!(r#"
# frozen_string_literal: true

"example"
"#).unwrap();
let fstring = s.as_interned_str().unwrap();
assert_eq!(fstring.as_slice(), &[101, 120, 97, 109, 112, 108, 101]);

pub fn test_as_str(self) -> Option<&'static str>

Returns the interned string as a &str or None string contains invliad UTF-8.

Examples

use magnus::{eval, RString};

let s: RString = eval!(r#"# frozen_string_literal: true
"example"
"#).unwrap();
let fstring = s.as_interned_str().unwrap();
assert_eq!(fstring.test_as_str().unwrap(), "example");

pub fn as_str(self) -> Result<&'static str, Error>

Returns the interned string as a &str. Errors if the string contains invliad UTF-8.

Examples

use magnus::{eval, RString};

let s: RString = eval!(r#"# frozen_string_literal: true
"example"
"#).unwrap();
let fstring = s.as_interned_str().unwrap();
assert_eq!(fstring.as_str().unwrap(), "example");

pub fn to_string_lossy(self) -> Cow<'static, str>

Returns interned string as a Rust string, ignoring the Ruby encoding and dropping any non-UTF-8 characters. If the string is valid UTF-8 this will return a &str reference.

Examples

use magnus::{eval, RString};

let s: RString = eval!(r#"
# frozen_string_literal: true

"example"
"#).unwrap();
let fstring = s.as_interned_str().unwrap();
assert_eq!(fstring.to_string_lossy(), "example");

Methods from Deref<Target = Value>

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");

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 never give Ruby a chance to free the string.
let s = unsafe { value.classname() }.into_owned();
assert_eq!(s, "Hash");

Trait Implementations

impl Clone for FString

fn clone(&self) -> FString

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for FString

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

Formats the value using the given formatter.

impl Deref for FString

type Target = Value

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl Display for FString

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

Formats the value using the given formatter.

impl From<FString> for Value

fn from(val: FString) -> Self

Converts to this type from the input type.

impl Copy for FString

impl ReprValue for FString