Extend "either <element> or text" constraint to support multiple element options

🚀 Feature Request

Summary

t would be helpful to extend existing constraint templates that currently support a binary choice — e.g., "must contain either or text" — to allow multiple valid element options. For example: "...must contain either <element 1> or <element 2> or text."

This pattern of allowing multiple alternatives is broadly applicable and should not be limited to the template Mandatory Content alone.

Problem to Solve / User Story

As a data modeler working with mixed content types like ConceptMixedComplexType, I want to define rules that allow more than one valid element type in addition to text, so that constraints can reflect the full flexibility of the LIDO 1.1 schema.

This would also make it possible to validate cases where an element must contain either a literal (e.g., Term) or a URI (e.g., Concept Identifier) — a common structure in semantic data. Currently, such combinations cannot be fully modeled using the existing template.

Moreover, similar multi-option requirements arise in other constraint scenarios beyond "text or element". For example:

“Element must contain either or ”

“Element must not contain or ”

“Element must contain only one of: , , or ”

Proposed Solution

Extend the current template to allow selecting multiple valid elements (e.g., Term, Concept Identifier, skos:Concept) as valid content in addition to text. The UI should support selecting two or more elements when defining the rule.

This would turn the current logic: ... must contain either or text into something like: ... must contain either <element 1> or <element 2> or text.

Benefits

Allows more accurate and schema-compliant constraints for mixed content elements.

Increases flexibility and usability of the tool.

Reduces the need for workarounds or incomplete validation rules.

Relevant Logs or Screenshots (if applicable)

Requirements or Dependencies

Support of multi-element selection.

Backend needs to support multiple options.