NAME

Clay::UI::_validate - internal attribute validation for Clay::UI widgets

DESCRIPTION

Functions the widget roles call from their constructors and accessors, so a bad attribute dies where it is set instead of when the tree is rendered. optional and required wrap a validator for the one-argument write of an accessor (optional accepts undef). Each validator takes the attribute name (used in the message) and the value, dies with Clay::UI: '<name>' ... when the value is wrong, and otherwise returns the value: the Clay validators return a deep copy (copy_value) with snake_case keys (snake_keys), so a widget never shares a hash or array with the caller that passed it and stores one spelling of every key, and accessors return copies of what they hold. Objects with overloading (value objects such as Math::BigInt numbers) are kept as they are.

Clay values are checked by "CHECKING STRUCTS" in Clay::XS: clay_struct($type) returns a validator for a whole struct (for example Clay_LayoutConfig), clay_field($type, $field) one for a single field of it (for example fontSize of Clay_TextElementConfig). Keys may be snake_case or camelCase and are stored in snake_case; both spellings of one key in a hash die. Errors name the attribute and the snake_case path inside it, e.g. Clay::UI: 'layout.padding.left' expected an integer in 0..65535, got '-5', and list the known keys for an unknown one.

The other validators hold Clay::UI's own rules: element ids must not start with anon:, user sizing-group ids must stay at or below USER_GROUP_ID_MAX (2**20 - 1; Clay::UI::Grid packs its own ids above it), text must be a defined string, and border_width may also be a single number.

is_finite_number is true for a plain number that is neither NaN nor infinite. copy_value deep-copies hashes and arrays (blessed ones into plain data) and keeps scalars and objects with overloading as they are.

This module is internal. The API is not part of the public contract.