README.md

runtime-struct-field-names-as-array

Provides the FieldNamesAsArray procedural macro. The macro adds the fn field_names_as_array() to the struct the macro is derived on. It contains the field names of the given struct, including the parents

Note: The macro can only be derived from named structs.

IMPORTANT This crate has a runtime overhead while it has limited options. If you do NOT intend to use it on a nested struct, you shall use this crate instead. See discussion

Table of Contents

• Usage
• Attributes
  • Field Attributes
    • Flatten

Usage

You can derive the FieldNamesAsArray macro like this:

use runtime_struct_field_names_as_array::FieldNamesAsArray;

#[derive(FieldNamesAsArray)]
struct Foo {
  bar: String,
  baz: String,
  bat: String,
}

assert_eq!(Foo::field_names_as_array(), ["bar", "baz", "bat"]);

Attributes

The FieldNamesAsArray macro supports the field_names_as_array attribute. field_names_as_array can be applied to a field with only the flatten attribute

Container Attributes

Container attributes are global attributes that change the behavior of the whole field names array, rather than that of a single field.

Field Attributes

Field attributes can be added to the fields of a named struct and change the behavior of a single field.

Flatten

The flatten attribute will add the parent fields. Option struct are also supported. If the attribute is not added on a struct type, it will be considered as a regular field.

use runtime_struct_field_names_as_array::FieldNamesAsArray;

#[derive(FieldNamesAsArray)]
struct Parent {
  foo: String,
}

#[derive(FieldNamesAsArray)]
struct Foo {
  bar: String,
  baz: String,
  #[field_names_as_array(flatten)]
  parent: Parent,
  #[field_names_as_array(flatten)]
  parent_option: Option<Parent>,
  another_parent: Parent,
}

assert_eq!(Foo::field_names_as_array(), ["bar", "baz", "parent.foo", "parent_option.foo", "another_parent"]);