Client-side logic

Not all UI behavior needs a server round-trip.

Mateu supports client-side logic declaratively through rules and related browser-side mechanisms.

Typical examples

Client-side logic is useful for things like:

• hiding or showing fields
• changing validation dynamically
• changing required / disabled state
• updating values
• changing styles or classes

Rules

The main mechanism for this is @Rule.

Rules are evaluated in the browser and can:

• change field attributes
• update state
• run actions
• execute JavaScript
• apply styles or CSS classes

Triggers vs rules

• triggers define when actions run
• rules define how the UI changes dynamically in the browser

Why this matters

This gives you dynamic behavior without introducing a separate frontend application layer.