Attempt to implement partial support (unfinished)

Author: theodorejb

composer.json

@@ -24,7 +24,7 @@
         "devtheorem/php-handlebars-parser": "dev-master"
     },
     "require-dev": {
-        "friendsofphp/php-cs-fixer": "^3.93",
+        "friendsofphp/php-cs-fixer": "^3.94",
         "jbboehr/handlebars-spec": "dev-master",
         "phpstan/phpstan": "^2.1.38",
         "phpunit/phpunit": "^11.5"

composer.lock

@@ -47,7 +47,10 @@ public static function precompile_new(string $template, Options $options = new O
         $context = new Context($options);
         $parser = (new ParserFactory())->create();
         $program = $parser->parse($template);
-        $code = (new NewCompiler())->compile($program, $context);
+        $compiler = new NewCompiler();
+        $code = $compiler->compile($program, $context);
+        $compiler->handleDynamicPartials();
+        static::handleError($context);
 
         // return full PHP render code as string
         return Compiler::composePHPRender($context, $code);

src/Handlebars.php

@@ -21,6 +21,7 @@
 use DevTheorem\HandlebarsParser\Ast\StringLiteral;
 use DevTheorem\HandlebarsParser\Ast\SubExpression;
 use DevTheorem\HandlebarsParser\Ast\UndefinedLiteral;
+use DevTheorem\HandlebarsParser\ParserFactory;
 
 /**
  * @internal
@@ -76,7 +77,7 @@ private function compileProgram(Program $program, bool $withSp = false): string
     private function accept(Node $node): string
     {
         return match (true) {
-            $node instanceof BlockStatement && $node->type === 'DecoratorBlock' => $this->DecoratorBlock(),
+            $node instanceof BlockStatement && $node->type === 'DecoratorBlock' => $this->DecoratorBlock($node),
             $node instanceof BlockStatement => $this->BlockStatement($node),
             $node instanceof PartialStatement => $this->PartialStatement($node),
             $node instanceof PartialBlockStatement => $this->PartialBlockStatement($node),
@@ -268,9 +269,23 @@ private function compileBlockHelper(BlockStatement $block, string $helperName):
         return "'." . $this->getFuncName('hbbch', "\$cx, '$helperName', $params, \$in, false, function(\$cx, \$in) {return $body;}$else") . ").'";
     }
 
-    private function DecoratorBlock(): string
+    private function DecoratorBlock(BlockStatement $block): string
     {
-        return ''; // todo: throw?
+        $helperName = $this->getSimpleHelperName($block->path);
+
+        if ($helperName !== 'inline' || count($block->params) !== 1 || !$block->params[0] instanceof StringLiteral) {
+            return '';
+        }
+
+        $partialName = $block->params[0]->value;
+        $body = $block->program ? $this->compileProgram($block->program, true) : "''";
+
+        // Register at compile time so {{> partialName}} can find it
+        $func = "function (\$cx, \$in, \$sp) {{$this->context->fStart}$body{$this->context->fEnd}}";
+        $this->context->usedPartial[$partialName] = '';
+        $this->context->partialCode[$partialName] = Expression::quoteString($partialName) . " => $func";
+
+        return "'." . $this->getFuncName('in', "\$cx, '" . addcslashes($partialName, "'\\") . "', function(\$cx, \$in, \$sp) {return $body;}") . ").'";
     }
 
     private function Decorator(Decorator $decorator): string
@@ -284,8 +299,10 @@ private function PartialStatement(PartialStatement $statement): string
 
         if ($name instanceof PathExpression) {
             $p = "'" . addcslashes($name->original, "'\\") . "'";
+            $this->resolveAndCompilePartial($name->original);
         } elseif ($name instanceof SubExpression) {
             $p = $this->SubExpression($name);
+            $this->context->usedDynPartial++;
         } else {
             $p = $this->compileExpression($name);
         }
@@ -303,14 +320,37 @@ private function PartialBlockStatement(PartialBlockStatement $statement): string
         $pid = $this->partialBlockId;
 
         $name = $statement->name;
+        $body = $this->compileProgram($statement->program, true);
+        $found = false;
 
         if ($name instanceof PathExpression) {
             $p = "'" . addcslashes($name->original, "'\\") . "'";
+            $partialName = $name->original;
+
+            if (!isset($this->context->usedPartial[$partialName])
+                && !str_starts_with($partialName, '@partial-block')
+            ) {
+                $resolveName = $partialName;
+                $cnt = Partial::resolve($this->context, $resolveName);
+                if ($cnt !== null) {
+                    $this->context->usedPartial[$resolveName] = $cnt;
+                    $this->compilePartialTemplate($resolveName, $cnt);
+                    $found = true;
+                }
+            } else {
+                $found = isset($this->context->usedPartial[$partialName]);
+            }
+
+            if (!$found) {
+                // Register fallback body as the partial
+                $func = "function (\$cx, \$in, \$sp) {{$this->context->fStart}$body{$this->context->fEnd}}";
+                $this->context->usedPartial[$partialName] = '';
+                $this->context->partialCode[$partialName] = Expression::quoteString($partialName) . " => $func";
+            }
         } else {
             $p = $this->compileExpression($name);
         }
 
-        $body = $this->compileProgram($statement->program, true);
         $vars = $this->compilePartialParams($statement->params, $statement->hash);
         $sp = "(\$sp ?? '') . ''";
 
@@ -454,8 +494,8 @@ private function PathExpression(PathExpression $expression): string
             if ($p !== '' && $depth === 0) {
                 $checks[] = "isset($base$p)";
             }
-                $baseP = "$base$p";
-                $checks[] = $baseP === '$in' ? '$inary' : "is_array($base$p)";
+            $baseP = "$base$p";
+            $checks[] = $baseP === '$in' ? '$inary' : "is_array($base$p)";
 
             $cond = implode(' && ', $checks);
             if (count($checks) > 1) {
@@ -506,6 +546,77 @@ private function Hash(Hash $hash): string
         return implode(',', $pairs);
     }
 
+    // ── Partials ─────────────────────────────────────────────────────
+
+    private function resolveAndCompilePartial(string $name): void
+    {
+        if (isset($this->context->usedPartial[$name])) {
+            return;
+        }
+
+        // @partial-block is resolved at runtime via LR::in()/LR::p()
+        if (str_starts_with($name, '@partial-block')) {
+            return;
+        }
+
+        $cnt = Partial::resolve($this->context, $name);
+
+        if ($cnt !== null) {
+            $this->context->usedPartial[$name] = $cnt;
+            $this->compilePartialTemplate($name, $cnt);
+            return;
+        }
+
+        $this->context->error[] = "The partial $name could not be found";
+    }
+
+    private function compilePartialTemplate(string $name, string $template): void
+    {
+        if (isset($this->context->partialCode[$name])) {
+            return;
+        }
+
+        // Prevent infinite recursion
+        if (end($this->context->partialStack) === $name && str_starts_with($name, '@partial-block')) {
+            return;
+        }
+
+        $tmpContext = clone $this->context;
+        $tmpContext->inlinePartial = [];
+        $tmpContext->partialBlock = [];
+        $tmpContext->partialStack[] = $name;
+
+        $program = (new ParserFactory())->create()->parse($template);
+        $code = (new NewCompiler())->compile($program, $tmpContext);
+        $this->context->merge($tmpContext);
+
+        if (!$this->context->options->preventIndent) {
+            $code = preg_replace('/^/m', "'{$this->context->separator}\$sp{$this->context->separator}'", $code);
+            // remove extra spaces before partial
+            $code = preg_replace('/^\'\\.\\$sp\\.\'(\'\\.LR::p\\()/m', '$1', $code, 1);
+            // remove extra spaces before section
+            $code = preg_replace('/^\'\\.\\$sp\\.\'(\'\\.LR::sec\\()/m', '$1', $code, 1);
+            // remove extra spaces before blank lines
+            $code = preg_replace('/^\'\\.\\$sp\\.\'(\';}\\))/m', '$1', $code, 1);
+            // add spaces after partial
+            $code = preg_replace('/^(\'\\.LR::p\\(.+\\)\\.)(\'.+)/m', '$1\$sp.$2', $code, 1);
+        }
+
+        $func = "function (\$cx, \$in, \$sp) {{$this->context->fStart}'$code'{$this->context->fEnd}}";
+        $this->context->partialCode[$name] = Expression::quoteString($name) . " => $func";
+    }
+
+    public function handleDynamicPartials(): void
+    {
+        if ($this->context->usedDynPartial === 0) {
+            return;
+        }
+
+        foreach ($this->context->partials as $name => $code) {
+            $this->resolveAndCompilePartial($name);
+        }
+    }
+
     // ── Helpers ──────────────────────────────────────────────────────
 
     /**
@@ -535,7 +646,7 @@ private function compileParams(array $params, ?Hash $hash, ?array $blockParams =
     private function compilePartialParams(array $params, ?Hash $hash): string
     {
         if (!$params) {
-            $contextVar = $this->context->options->explicitPartialContext ? 'null' : '';
+            $contextVar = $this->context->options->explicitPartialContext ? 'null' : '$in';
         } else {
             $contextVar = $this->compileExpression($params[0]);
         }

src/NewCompiler.php

@@ -300,6 +300,11 @@ public static function p(RuntimeContext $cx, string $p, $v, int $pid, string $sp
 
         $cx = clone $cx;
         $cx->partialId = ($p === '@partial-block') ? ($pid > 0 ? $pid : ($cx->partialId > 0 ? $cx->partialId - 1 : 0)) : $pid;
+        $cx->partialDepth++;
+
+        if ($cx->partialDepth > 100) {
+            throw new \Exception("Runtime: the partial $p could not be found");
+        }
 
         return $cx->partials[$pp]($cx, static::merge($v[0][0], $v[1]), $sp);
     }

src/Runtime.php

@@ -21,5 +21,6 @@ public function __construct(
         public array $spVars = [],
         public array $blParam = [],
         public int $partialId = 0,
+        public int $partialDepth = 0,
     ) {}
 }