Trait scrypto::prelude::ContextualDisplay
pub trait ContextualDisplay<Context> {
type Error;
// Required method
fn contextual_format<F>(
&self,
f: &mut F,
context: &Context
) -> Result<(), Self::Error>
where F: Write;
// Provided methods
fn format<F, TContext>(
&self,
f: &mut F,
context: TContext
) -> Result<(), Self::Error>
where F: Write,
TContext: Into<Context> { ... }
fn display<TContext, 'a, 'b>(
&'a self,
context: TContext
) -> ContextDisplayable<'a, Self, Context>
where TContext: Into<Context> { ... }
fn to_string<TContext, 'a, 'b>(&'a self, context: TContext) -> String
where TContext: Into<Context> { ... }
}Expand description
This trait is used where context is required to correctly display a value.
Typically, this is due to needing to know the current network to display addresses.
Other forms of Context are also possible. See ComponentAddress
or TransactionReceipt in the radix-engine crate for example implementations.
The Context used should typically just be a wrapper type around references, and so
be a small, cheap, ephemeral value on the stack (if it’s not just optimized away entirely).
It is therefore recommended that the Context implement Copy,
to make it very easy to pass around and re-use.
Required Associated Types§
type Error
Required Methods§
Provided Methods§
fn format<F, TContext>(
&self,
f: &mut F,
context: TContext
) -> Result<(), Self::Error>
fn format<F, TContext>( &self, f: &mut F, context: TContext ) -> Result<(), Self::Error>
Formats the value to the given fmt::Write buffer, making use of the provided context.
See also contextual_format, which takes a &Context instead of an Into<Context>.
Alternatively, the display method can be used to create an object that can be used
directly in a format! style macro.
fn display<TContext, 'a, 'b>(
&'a self,
context: TContext
) -> ContextDisplayable<'a, Self, Context>where
TContext: Into<Context>,
fn display<TContext, 'a, 'b>(
&'a self,
context: TContext
) -> ContextDisplayable<'a, Self, Context>where
TContext: Into<Context>,
Returns an object implementing fmt::Display, which can be used in a format! style macro.
Whilst this is syntactically nicer, beware that the use of format! absorbs any errors during
formatting, replacing them with fmt::Error.
If you’d like to preserve errors, use the format method instead. This may require manually
splitting up your format! style macro. For example:
// Syntactically nice, but the AddressError is swallowed into fmt::Error
write!(f, "ComponentAddress(\"{}\")", address.display(context))?;
// Less nice, but the AddressError is correctly returned
f.write_str("ComponentAddress(\"")?;
address.format(f, context)?;
f.write_str("\")")?;