AttributeTarget

Module std.meta

import std.meta;

Public declaration contracts and authored examples. A page can document several related symbols. Implementation bodies are excluded.

AttributeTarget

pub enum AttributeTarget

Identifies one semantic declaration target accepted by typed metadata.

Targets describe declarations and their structural subdeclarations rather than syntax positions. .Any is exclusive when used by AttributeUsage.

Example

module example.attribute_policy;
from std.meta import AttributeRetention, AttributeTarget, AttributeUsage;

[AttributeUsage(.Field, Repeatable = true, Retention = .Runtime)]
[AttributeUsage(.Global, Repeatable = true, Retention = .Runtime)]
pub attribute Label {
    pub Text: str;
    init(Text: str) { this.Text = Text; }
}

[AttributeUsage(.Type, Retention = .CompileTimeOnly)]
pub attribute BuildHint { init() { } }

[BuildHint]
pub struct Record {
    [Label("identifier"), Label("database key")]
    pub Id: u64;
}

[Label("current record count")]
pub var RecordCount: i32 = 0;

fn Main() -> i32 { RecordCount += 1; return RecordCount; }

AttributeTarget.Any

Any;

Selects every legal semantic target and cannot be combined with another target.

AttributeTarget.Module

Module;

Selects a source module declaration.

AttributeTarget.Type

Type;

Selects a nominal or synonym type declaration.

AttributeTarget.Concept

Concept;

Selects a structural concept declaration.

AttributeTarget.Constant

Constant;

Selects a typed constant declaration.

AttributeTarget.Field

Field;

Selects a stored field declaration.

AttributeTarget.Property

Property;

Selects an instance property declaration.

AttributeTarget.Function

Function;

Selects an ordinary or external function declaration.

AttributeTarget.Initializer

Initializer;

Selects an initializer declaration.

AttributeTarget.Deinitializer

Deinitializer;

Selects a deinitializer declaration.

AttributeTarget.Operator

Operator;

Selects an operator declaration.

AttributeTarget.Getter

Getter;

Selects a property getter subdeclaration.

AttributeTarget.Setter

Setter;

Selects a property setter subdeclaration.

AttributeTarget.Parameter

Parameter;

Selects one named callable parameter.

AttributeTarget.Return

Return;

Selects one callable return subdeclaration.

AttributeTarget.GenericParameter

GenericParameter;

Selects one named generic parameter.

AttributeTarget.EnumCase

EnumCase;

Selects one enum case declaration.

AttributeTarget.Global

Global;

Selects a module runtime storage declaration.