validator

type CustomTypeFunc = func(field reflect.Value) any

type ValidationRule struct {
	// RuleTag is the struct-tag keyword that activates the rule (e.g. "dec_min"
	// for `validate:"dec_min=10"`). It must be unique across registered rules.
	RuleTag string
	// ErrMessageTemplate is the fallback message used when no i18n translation
	// resolves for ErrMessageI18nKey. It may contain {N} placeholders filled
	// from ParseParam in order ({0} is the first element, {1} the second).
	ErrMessageTemplate string
	// ErrMessageI18nKey is the i18n key looked up first to render the error
	// message; when it resolves, the translated text receives the same {N}
	// placeholder substitution as ErrMessageTemplate. Leave empty to always use
	// ErrMessageTemplate.
	ErrMessageI18nKey string
	// Validate reports whether the field value satisfies the rule. It returns
	// true when valid; the rule parameter (right of '=') is available via
	// fl.Param().
	Validate func(fl v.FieldLevel) bool
	// ParseParam returns the ordered substitution values for the message
	// placeholders ({0}, {1}, ...) for a failing field, typically the field
	// name and the rule parameter.
	ParseParam func(fe v.FieldError) []string
	// CallValidationEvenIfNull maps to go-playground's callEvenIfNull: when
	// true, Validate is invoked even for nil/zero fields. Leave false unless the
	// rule must inspect absent values.
	CallValidationEvenIfNull bool
}