Trait LanguageBackend

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pub trait LanguageBackend {
Show 19 methods    // Required methods
    fn scalar_to_type(&self, scalar: &ScalarType) -> &'static str;
    fn array_type(&self, inner: &str) -> String;
    fn not_in_suffix(&self) -> &'static str;
    fn startswith_suffix(&self) -> &'static str;
    fn endswith_suffix(&self) -> &'static str;
    fn null_suffix(&self) -> &'static str;
    fn null_literal(&self) -> &'static str;
    fn true_literal(&self) -> &'static str;
    fn false_literal(&self) -> &'static str;
    fn string_literal(&self, s: &str) -> String;
    fn empty_array_literal(&self) -> &'static str;

    // Provided methods
    fn is_auto_generated(&self, field: &FieldIr) -> bool { ... }
    fn numeric_operators(&self, type_name: &str) -> Vec<FilterOperator> { ... }
    fn get_filter_operators_for_scalar(
        &self,
        scalar: &ScalarType,
    ) -> Vec<FilterOperator> { ... }
    fn get_filter_operators_for_field(
        &self,
        field: &FieldIr,
        enums: &HashMap<String, EnumIr>,
    ) -> Vec<FilterOperator> { ... }
    fn enum_variant_literal(&self, variant: &str) -> String { ... }
    fn relation_type(&self, target_model: &str) -> String { ... }
    fn get_base_type(
        &self,
        field: &FieldIr,
        enums: &HashMap<String, EnumIr>,
    ) -> String { ... }
    fn get_default_value(&self, field: &FieldIr) -> Option<String> { ... }
}

Expand description

Common interface for language-specific code generation backends.

§Abstract methods

Backends must implement the four type-mapping primitives and the four operator-naming conventions.

§Default methods

Everything else — is_auto_generated, the numeric-operator helper, and the full filter-operator builders — is provided as a default implementation that composes the abstract methods. Backends only override these defaults when their language genuinely diverges from the shared logic.

Required Methods§

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fn scalar_to_type(&self, scalar: &ScalarType) -> &'static str

Maps a Nautilus scalar type to the target language’s type name.

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fn array_type(&self, inner: &str) -> String

Wraps a type name in the language’s array/list syntax.

Examples: "List[T]" (Python) vs "T[]" (TypeScript).

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fn not_in_suffix(&self) -> &'static str

Suffix for the “not in collection” operator.

Python: "not_in" — TypeScript: "notIn"

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fn startswith_suffix(&self) -> &'static str

Suffix for the “starts with” string operator.

Python: "startswith" — TypeScript: "startsWith"

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fn endswith_suffix(&self) -> &'static str

Suffix for the “ends with” string operator.

Python: "endswith" — TypeScript: "endsWith"

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fn null_suffix(&self) -> &'static str

Suffix for the null-check operator.

Python: "is_null" — TypeScript: "isNull"

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fn null_literal(&self) -> &'static str

The null literal in this language (Python: "None", TS: "null").

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fn true_literal(&self) -> &'static str

The boolean true literal (Python: "True", TS: "true").

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fn false_literal(&self) -> &'static str

The boolean false literal (Python: "False", TS: "false").

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fn string_literal(&self, s: &str) -> String

Format a string literal (Python: "\"hello\"", TS: "'hello'").

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fn empty_array_literal(&self) -> &'static str

The empty-array factory expression (Python: "Field(default_factory=list)", TS: "[]").

Provided Methods§

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fn is_auto_generated(&self, field: &FieldIr) -> bool

Returns true for fields whose values are supplied automatically by the database: autoincrement(), uuid(), or now().

This implementation is identical for Python and TypeScript. The Rust backend intentionally differs (it exposes now() fields as writable), which is why it lives in type_helpers.rs and does not use this trait.

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