Trait scrypto_test::prelude::fmt::Debug

1.0.0 · source ·

pub trait Debug {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}

Expand description

? formatting.

Debug should format the output in a programmer-facing, debugging context.

Generally speaking, you should just derive a Debug implementation.

When used with the alternate format specifier #?, the output is pretty-printed.

For more information on formatters, see the module-level documentation.

This trait can be used with #[derive] if all fields implement Debug. When derived for structs, it will use the name of the struct, then {, then a comma-separated list of each field’s name and Debug value, then }. For enums, it will use the name of the variant and, if applicable, (, then the Debug values of the fields, then ).

§Stability

Derived Debug formats are not stable, and so may change with future Rust versions. Additionally, Debug implementations of types provided by the standard library (std, core, alloc, etc.) are not stable, and may also change with future Rust versions.

§Examples

Deriving an implementation:

#[derive(Debug)]
struct Point {
    x: i32,
    y: i32,
}

let origin = Point { x: 0, y: 0 };

assert_eq!(format!("The origin is: {origin:?}"), "The origin is: Point { x: 0, y: 0 }");

Manually implementing:

use std::fmt;

struct Point {
    x: i32,
    y: i32,
}

impl fmt::Debug for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Point")
         .field("x", &self.x)
         .field("y", &self.y)
         .finish()
    }
}

let origin = Point { x: 0, y: 0 };

assert_eq!(format!("The origin is: {origin:?}"), "The origin is: Point { x: 0, y: 0 }");

There are a number of helper methods on the Formatter struct to help you with manual implementations, such as debug_struct.

Types that do not wish to use the standard suite of debug representations provided by the Formatter trait (debug_struct, debug_tuple, debug_list, debug_set, debug_map) can do something totally custom by manually writing an arbitrary representation to the Formatter.

impl fmt::Debug for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "Point [{} {}]", self.x, self.y)
    }
}

Debug implementations using either derive or the debug builder API on Formatter support pretty-printing using the alternate flag: {:#?}.

Pretty-printing with #?:

#[derive(Debug)]
struct Point {
    x: i32,
    y: i32,
}

let origin = Point { x: 0, y: 0 };

assert_eq!(format!("The origin is: {origin:#?}"),
"The origin is: Point {
    x: 0,
    y: 0,
}");

Required Methods§

source

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

Formats the value using the given formatter.

§Examples

use std::fmt;

struct Position {
    longitude: f32,
    latitude: f32,
}

impl fmt::Debug for Position {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple("")
         .field(&self.longitude)
         .field(&self.latitude)
         .finish()
    }
}

let position = Position { longitude: 1.987, latitude: 2.983 };
assert_eq!(format!("{position:?}"), "(1.987, 2.983)");

assert_eq!(format!("{position:#?}"), "(
    1.987,
    2.983,
)");

Trait scrypto_test::prelude::fmt::Debug

§Stability

§Examples

Required Methods§

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

§Examples

Implementors§

impl Debug for AccountCollection

impl Debug for AccountFeature

impl Debug for AccountField

impl Debug for AccountTypedFieldSubstateValue

impl Debug for AccountTypedSubstateKey

impl Debug for AccountTypedSubstateValue

impl Debug for VersionedAccountAuthorizedDepositor

impl Debug for VersionedAccountDepositRule

impl Debug for VersionedAccountResourcePreference

impl Debug for VersionedAccountResourceVault

impl Debug for AccountError

impl Debug for radix_engine::blueprints::account::events::DepositEvent

impl Debug for RejectedDepositEvent

impl Debug for radix_engine::blueprints::account::events::WithdrawEvent

impl Debug for MetadataError

impl Debug for MetadataValidationError

impl Debug for MetadataCollection

impl Debug for MetadataFeature

impl Debug for MetadataField

impl Debug for MetadataTypedFieldSubstateValue

impl Debug for MetadataTypedSubstateKey

impl Debug for MetadataTypedSubstateValue

impl Debug for VersionedMetadataEntry

impl Debug for RoleAssignmentError

impl Debug for RoleAssignmentCollection

impl Debug for RoleAssignmentFeature

impl Debug for RoleAssignmentField

impl Debug for RoleAssignmentTypedFieldSubstateValue

impl Debug for RoleAssignmentTypedSubstateKey

impl Debug for RoleAssignmentTypedSubstateValue

impl Debug for VersionedRoleAssignmentAccessRule

impl Debug for VersionedRoleAssignmentOwner

impl Debug for ComponentRoyaltyCollection

impl Debug for ComponentRoyaltyFeature

impl Debug for ComponentRoyaltyField

impl Debug for ComponentRoyaltyTypedFieldSubstateValue

impl Debug for ComponentRoyaltyTypedSubstateKey

impl Debug for ComponentRoyaltyTypedSubstateValue

impl Debug for VersionedComponentRoyaltyAccumulator

impl Debug for VersionedComponentRoyaltyMethodAmount

impl Debug for ComponentRoyaltyError

impl Debug for ComponentRoyaltyDatabaseCheckerError

impl Debug for ErrorLocation

impl Debug for KernelDatabaseCheckError

impl Debug for PackageRoyaltyDatabaseCheckerError

impl Debug for ResourceReconciliationError

impl Debug for RoleAssignmentDatabaseCheckerError

impl Debug for NodeInfo

impl Debug for SystemDatabaseCheckError

impl Debug for SystemNodeCheckError

impl Debug for SystemNodeType

impl Debug for SystemPartitionCheckError

impl Debug for SystemEventCheckerError

impl Debug for IDAllocation

impl Debug for SchemaOrigin

impl Debug for TypeInfoForValidation

impl Debug for ObjectPartitionDescriptor

impl Debug for SystemPartitionDescription

impl Debug for SystemPartitionDescriptor

impl Debug for SystemReaderError

impl Debug for SchemaValidationMeta

impl Debug for TypeCheckError

impl Debug for TypeInfoSubstate

impl Debug for StaleTreePart

impl Debug for TreeNodeV1

impl Debug for VersionedTreeNode

impl Debug for CreationStrategy

impl Debug for FactoryResourceSpecifier

impl Debug for CostingError

impl Debug for FeeReserveError

impl Debug for OnApplyCost

impl Debug for RoyaltyRecipient

impl Debug for scrypto_test::prelude::costing::StorageType