`Field`¶

Stability

Classifications for this surface are recorded in STABILITY.md.

Status: Accepted · Shipped (current train 1.1.x)

Field declares validation, presentation, security, and data-editing metadata on Model / FormModel attributes. It returns a Pydantic FieldInfo with Hedron metadata.

from decimal import Decimal

from hedron import Field, Model, Secret

class EmployeeRow(Model):
    employee_id: int = Field(label="ID", read_only=True)
    salary: Decimal = Field(minimum=0, display="currency")
    password: Secret = Field(autocomplete="current-password")

Signature¶

def Field(
    default: Any = ...,
    *,
    default_factory: Any = None,
    # Validation
    minimum: float | int | None = None,
    maximum: float | int | None = None,
    min_length: int | None = None,
    max_length: int | None = None,
    pattern: str | None = None,
    choices: list[Any] | tuple[Any, ...] | None = None,
    required: bool | None = None,
    # Presentation
    label: str | None = None,
    help: str | None = None,
    placeholder: str | None = None,
    display: str | None = None,
    autocomplete: str | None = None,
    format: str | None = None,
    # Access
    read_only: bool = False,
    hidden: bool = False,
    secret: bool = False,
    writable_policy: str | None = None,
    # Data
    key: str | None = None,
    sortable: bool = False,
    filterable: bool = False,
    editor: str | None = None,
    width: str | int | None = None,
    identity: bool = False,
    # Accessibility
    accessible_label: str | None = None,
    accessible_description: str | None = None,
    accessible_error: str | None = None,
) -> Any: ...

Parameters¶

Parameter	Group	Meaning
`default` / `default_factory`	Core	Default value or factory (Pydantic semantics)
`minimum` / `maximum`	Validation	Numeric bounds
`min_length` / `max_length` / `pattern`	Validation	String constraints
`choices` / `required`	Validation	Enumerations and required state
`label` / `help` / `placeholder` / `display` / `autocomplete` / `format`	Presentation	Form and table presentation
`read_only` / `hidden` / `secret` / `writable_policy`	Access	Access metadata (not authorization)
`key` / `sortable` / `filterable` / `editor` / `width` / `identity`	Data	Table/editor hints
`accessible_label` / `accessible_description` / `accessible_error`	Accessibility	ATIA-oriented metadata

Returns¶

A Pydantic FieldInfo carrying Hedron metadata for forms, tables, DataEditor, examples, OpenAPI extensions, and Explorer.

Errors¶

Code	When
`HED-MODEL-0001`	Contradictory combinations (`read_only` + `writable_policy`; `secret` + `display="plaintext"`; `secret` + `identity`)
`HED-MODEL-0002`	Unknown keyword options in `**extra`
`HED-MODEL-0003`+	Additional model/field diagnostics may appear from the model system—see error codes and source

Metadata may guide forms, tables, DataEditor, examples, OpenAPI extensions, and Explorer. It never grants authorization or replaces business validation.

Field¶