Trait xso::FromOptionalXmlText

pub trait FromOptionalXmlText: Sized {
    // Required method
    fn from_optional_xml_text(s: Option<&str>) -> Result<Option<Self>, Error>;
}

Provide construction of a value from optional XML text data.

Most likely, you don’t need to implement this; implement FromXmlText instead (which automatically provides a FromOptionalXmlText implementation).

This trait has to exist to handle the special-ness of Option<_> when it comes to values which don’t always exist.

Required Methods

fn from_optional_xml_text(s: Option<&str>) -> Result<Option<Self>, Error>

Convert the XML string to a value, maybe.

This should return None if and only if s is None, but in some cases it makes sense to return Some(..) even for an input of None, e.g. when a specific default is desired.

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl<T: FromOptionalXmlText> FromOptionalXmlText for Option<T>

fn from_optional_xml_text(s: Option<&str>) -> Result<Option<Self>, Error>

This implementation returns Some(None) for an input of None.

That way, absent attributes with a Option<T> field type effectively default to None.

Implementors

impl<T: FromXmlText> FromOptionalXmlText for T