Diagnostics

A template or stylesheet can be valid HTML and CSS and still do nothing in RTXUI: a property the engine does not implement, a typo in a bound name, an attribute borrowed from another framework. Rather than ignore these silently, RTXUI reports each one as a diagnostic.

What Is Reported

Mistake	Example	Diagnostic
Unsupported CSS property or value	font-size: small, flex-direction: diagonal	unsupported CSS declaration 'font-size: small'
Interpolating a name that is not bound	{titel}	'{titel}' in <App> is not a bound name
An expression inside {}	{count == 1}	templates do not evaluate expressions; bind a const method computing the value and use its name
A handler that is not bound	onclick="Sumbit", when clicked	handler 'Sumbit' is not bound in any enclosing component
A tag that is not a built-in or an imported component	<View>, <Card/> without Import<Card>()	unknown tag <Card> in <App>: if it is your component, call Import<Card>() in <App>'s constructor
A <style> nested inside an element	<div><style>...</style></div>	<style> inside <div> in <App> is ignored: put <style> at the top level of the view
Another framework's attribute syntax	v-if, *ngFor, className, onClick, for="x in xs"	attribute 'v-if' on <div> in <App> is not RTXUI syntax: use if="{name}" or <if condition="{name}">

Each distinct message is reported once per run, even though styles are re-applied on every frame.

Where They Go

By default each diagnostic is printed to stderr, prefixed with rtxui:.

Set the environment variable RTXUI_STRICT=1 to abort on the first one instead. This is what RTXUI's own example test runs with, and it is a good setting for your tests and CI:

RTXUI_STRICT=1 ./my_app

An application that owns the terminal can route diagnostics through its own interface, since printing to stderr disturbs a running frame:

#include <rtxui/rtxui.hpp>

rtxui::SetDiagnosticHandler([](const rtxui::Diagnostic& d) {
  log_file << d.message << '\n';
});

Pass nullptr to restore the default.