Expand description

This crate provides procedural macrs to generate functions that return static slices of struct field names or enum variant names.

Examples

use fievar::Fields;

#[derive(Fields)]
struct File {
    id: String,
    name: String,
    mime_type: String,
}

assert_eq!(&["id", "name", "mime_type"], File::fields());

You can also rename fields.

use fievar::Fields;

#[derive(Fields)]
struct File {
    id: String,
    name: String,
    #[fievar(name = "mimeType")]
    mime_type: String,
}

assert_eq!(&["id", "name", "mimeType"], File::fields());

Transformations

Syntax

Expression:
   [[T][|Sep]]

Sep: Word separator.
   Can be any text.

T: Determines how to transform field/variant.
   [[TrCase][ NumAlign]]

NumAlign: Controls alignment of numerals.
   1__ | __1 | _1_

TrCase: Controls the case of letters.
   [TrWord[ TrWord[ TrWord]]]

TrWord: Controls the case of individual words.
   [TrChar[TrChar[TrChar]]]

TrChar: Controls the case of individual characters in words.
   c | C

TrCase consists of upto three TrWords separated by a space. If there is only one TrWord then it is used to transform all words in field/variant. If there are two TrWords then the first TrWord is applied to the first word of the field/variant and the second TrWord is applied to the rest of the words. If there are three TrWords then the first and last TrWords are applied to the first and last words of the field/variant and the second TrWord is applied to the rest of the words. TrChars work similarly on characters in a word.

Examples

use fievar::Variants;

#[derive(Variants)]
enum E {
    #[fievar(transform = "c")] // lowercase
    AVeryLong0Variant,

    #[fievar(transform = "C")] // uppercase
    AVeryLong1Variant,

    #[fievar(transform = "1__|_")] // align numeral left
    AVeryLong2Variant,

    #[fievar(transform = "__1|_")] // align numeral right
    AVeryLong3Variant,

    #[fievar(transform = "_1_|_")] // align numeral middle
    AVeryLong4Variant,

    #[fievar(transform = "c Cc")] // camelCase
    AVeryLong5Variant,

    #[fievar(transform = "c|_")] // snake_case
    AVeryLong6Variant,

    #[fievar(transform = "CcC cCc CcC _1_|*-*")] // something different
    LastVeryLong7Variant,
}

let v = &[
    "averylong0variant",
    "AVERYLONG1VARIANT",
    "A_Very_Long2_Variant",
    "A_Very_Long_3Variant",
    "A_Very_Long_4_Variant",
    "aVeryLong5Variant",
    "a_very_long6_variant",
    "LasT*-*vERy*-*lONg*-*7*-*VarianT"
];
assert_eq!(v, E::variants());

Derive Macros

Implements a fields method on structs that return an arry slice of struct field names.

Implements a variants method on enums that return an arry slice of enum variant names.