Crate es_fluent_lang 

es-fluent-lang

Runtime support for es-fluent language management.

This crate provides the core language types (re-exporting unic-langid) and the optional “Language Enum” generator macro.

Features

#[es_fluent_language]

Generates a strongly-typed enum of all available languages in your project. It automatically scans your i18n.toml assets directory to find supported locales.

use es_fluent_lang::es_fluent_language;
use es_fluent::EsFluent;
use strum::EnumIter;

// Define an empty enum, and the macro fills it
#[es_fluent_language]
#[derive(Debug, Clone, Copy, PartialEq, Eq, EsFluent, EnumIter)]
pub enum Languages {}

If your assets_dir contains en, fr, and de folders, this generates:

pub enum Languages {
    En,
    Fr,
    De,
}

It also implements:

• Default: Uses the fallback_language from your config.
• FromStr: Parses string codes (e.g., “en-US”) into the enum variant.
• TryFrom<&LanguageIdentifier> / TryFrom<LanguageIdentifier>: Converts from a locale ID and returns an error for unsupported locales.
• Into<LanguageIdentifier>: Converts back to a standard locale ID.

For user-facing labels, derive EsFluent on the generated enum and call to_fluent_string() instead of relying on Display.

Feature Flags

• macros (default): Enables the #[es_fluent_language] macro.
• localized-langs: Use per-locale resources under i18n/<locale>/es-fluent-lang.ftl instead of the embedded autonym file.
• bevy: Enables Bevy engine integration and force-link keepalive for module registration.

Standard Translations

The crate also includes a built-in module for translating language names themselves (e.g., “English”, “Français”, “Deutsch”). This means you can easily build a “Language Picker” UI without manually translating the names of every language.

By default, language names are loaded from the embedded es-fluent-lang.ftl autonym file (language names in their native scripts). With the localized-langs feature, names are loaded from per-locale resources under i18n/<locale>/es-fluent-lang.ftl (generated by cargo run -p xtask -- generate-lang-names from ICU4X data; see xtask/README.md). The runtime resolves fallback locales when needed (for example, zh-CN will fall back to zh).

When the bevy feature is enabled, this crate uses the same standard module registration as other managers and provides a small force-link keepalive hook for Bevy/WASM builds.

Macros

langid

Structs

LanguageIdentifier

LanguageIdentifier is a core struct representing a Unicode Language Identifier.

Attribute Macros

es_fluent_language

Attribute macro that expands a language enum based on the i18n.toml configuration. Which generates variants for each language in the i18n folder structure.