Conditionals and Control Flow

SqueHub's .squehub.php templates support @if, @unless, and @switch blocks. The template compiler checks their structure and emits ordinary PHP control flow. Conditional expressions are trusted PHP expressions evaluated at render time. The compiler does not evaluate them, interpret their meaning, or sandbox template code. Keep application decisions in controllers or services when they become complex.

If and elseif

@if ($user)
    Welcome, {{ $user->name }}
@elseif ($invited)
    Welcome, invited guest.
@else
    Welcome, guest.
@endif

@if and @elseif accept balanced, multiline expressions, including nested calls, arrays, quoted punctuation, and valid PHP 8.2 expressions:

@if (
    $user !== null
    && in_array($status, ['active', 'pending'], true)
)
    <p>Account available</p>
@endif

PHP evaluates each condition when the View renders. It retains normal short-circuit and branch behavior: an unselected branch does not execute its PHP or echoes. A compiled View can therefore render different branches on later requests without recompiling for a changed condition.

Unless

@unless renders its first branch when its expression is false. It accepts @else, but @elseif belongs to @if.

@unless ($maintenance)
    <main>...</main>
@else
    <p>Temporarily unavailable.</p>
@endunless

@unless expressions follow the same balanced, multiline PHP rules as @if.

Switch

@switch($status)
    @case('active')
        Active
        @break

    @case('pending')
        Pending
        @break

    @default
        Unknown
@endswitch

@switch and @case accept normal trusted PHP expressions, including multiline ones. They use PHP's normal switch comparison and fall-through behavior. SqueHub does not insert a break: adjacent cases may deliberately share a branch, and a case without @break continues to the next case. Bare @break works inside a switch, including within an @if nested in a case. In a nested switch, PHP's normal break targets the inner switch. Structured loops also support bare @break; conditional and depth arguments are unsupported. See Loops and Iteration State.

Between @switch(...) and its first @case or @default, only whitespace is allowed. The compiler consumes that whitespace as PHP syntax, so it produces no HTML. Other content before the first label is a template compile error. After a case or default label, ordinary template content and its whitespace render normally.

Structure and diagnostics

The compiler checks matching @endif, @endunless, and @endswitch directives, including nested blocks. It reports unmatched or unclosed blocks, mismatched endings, @elseif outside an open @if, @else outside @if or @unless, duplicate @else, @elseif after @else, @case or @default outside a switch, duplicate @default, and @break without an enclosing switch or loop. The compiler also rejects empty expressions and argument syntax on bare directives such as @else(...). Development diagnostics name the logical View and source line. Production HTTP errors use the application's safe exception boundary and do not expose template source or filesystem paths.

Directives can appear inline; they do not need separate lines. Names have lexical boundaries: @elseB is a different, unknown directive name, not @else followed by B. Write @else B or place markup after @else when literal content starts with a letter. Unknown @ text, CSS @media, and email addresses remain literal. Directives inside raw PHP, @php blocks, or protected JavaScript strings do not compile; HTML comments are removed, so directives inside them do not execute. PHP syntax errors inside otherwise balanced expressions remain PHP errors, not template structure errors.

View data, layouts, and output

Conditions can read the same values as the rest of a View: explicit render data, Application shared values, request providers, composers, and inherited layout or include data. An explicit include override affects that partial subtree without changing its parent. Conditions do not create a new context or change provider lifetime. See Shared View Context for precedence and isolation rules.

Conditions also work inside a captured section. The page can choose content with @if or @switch before its parent layout yields that section. The section is captured once per render, so yielding it twice does not rerun its conditions or their side effects. See Layouts and Sections for a page example and inheritance rules.

An asset declaration or @push block inside an @if branch runs only when that branch executes. Likewise, a partial included conditionally contributes its own scripts and styles only when it renders. The asset stacks guide explains ownership and final stack placement; a condition does not create a separate asset registry.

A layout can use the shared or explicit title value with a fallback:

@if (isset($title) && $title !== '')
    <title>{{ $title }}</title>
@else
    <title>My Application</title>
@endif

{{ $value }} remains HTML escaped in every branch. {!! $trustedHtml !!} remains raw output and requires trusted or separately sanitized HTML. Conditionals do not replace server-side authorization or input validation.

SqueHub provides structurally checked loops, bare loop-scoped @break and @continue, and read-only $loop metadata for @foreach and @forelse. A switch alone does not permit @continue; a switch nested inside a loop also blocks bare @continue unless another loop is nested inside that switch. See Loops and Iteration State. The legacy @do form remains compatible.