Tests if the context node allows a certain element
@param string $name Name of element to test for
@return bool True if element is allowed, false if it is not
503184
public function allowsElement($name)
    {
        if (!empty($this->currentNesting)) {
            $parent_token = array_pop($this->currentNesting);
            $this->currentNesting[] = $parent_token;
            $parent = $this->htmlDefinition->info[$parent_token->name];
        } else {
            $parent = $this->htmlDefinition->info_parent_def;
        }
        if (!isset($parent->child->elements[$name]) || isset($parent->excludes[$name])) {
            return false;
        }
        // check for exclusion
        for ($i = count($this->currentNesting) - 2; $i >= 0; $i--) {
            $node = $this->currentNesting[$i];
            $def  = $this->htmlDefinition->info[$node->name];
            if (isset($def->excludes[$name])) {
                return false;
            }
        }
        return true;
    }
262715
public function supports($name)
    {
        if ($name instanceof Template) {
            return true;
        }

        $template = $this->parser->parse($name);

        return 'twig' === $template->get('engine');
    }
737791
public function __isset($name)
    {
        return isset($this->children[$name]) && !is_null($this->children[$name]->getValue());
    }
1076959
public function has(string $name): bool
    {
        $name = $this->getDefinitiveName($name);

        return isset($this->instances[$name]);
    }
293882
public function has(string $name): bool
    {
        try {
            $this->dotGet($name);
        } catch (DotNotFoundException $e) {
            return false;
        }

        return true;
    }
1192249
public function hasElement( $name, $prefix = null )
	{
		return isset( $this->elements[ is_null( $prefix ) ? $name : "$prefix:$name" ] );
	}
1044887
public function hasOption(string $name) : bool
    {
        return in_array($name, self::$options) || in_array("^$name", self::$options);
    }
970530
protected function isWysiwygEnabled($name)
    {
        return isset($this->allowedWyswig[$name]) && (bool) $this->allowedWyswig[$name];
    }
600435
public function supports($name)
    {
        $name = (string)$name;

        if (isset($this->supportedTemplates[$name])) {
            return $this->supportedTemplates[$name];
        }

        // Template URI must begin by "design:" or "file:" and have a .tpl suffix
        $this->supportedTemplates[$name] =
            (
                strpos($name, 'design:') === 0 ||
                strpos($name, 'file:') === 0
            ) &&
            (substr($name, -\strlen(self::SUPPORTED_SUFFIX)) === self::SUPPORTED_SUFFIX);

        return $this->supportedTemplates[$name];
    }
1334589
public static function has($name)
    {
        return (self::find()->where([self::getNameAttribute() => $name])->one()) ? true : false;
    }
626243
public function hasExtraConfiguration($name)
    {
        $name = $this->resolveString($name, __METHOD__);

        return isset($this->extraConfiguration[$name]);
    }
972955
public function has($name)
    {
        $context = $this->_context;

        if (!$context->started) {
            $this->_start();
        }

        return isset($context->_SESSION[$name]);
    }
1172256
public function isUsed(string $name): bool
    {
        if (in_array($name, $this->usages)) {
            return true;
        }

        foreach ($this->children as $child) {
            if (!$child->isIsolated() && $child->isUsed($name)) {
                return true;
            }
        }

        return false;
    }
1183642
public function isProtected($name)
    {
        return (bool) (
            $this->_services_protected->offsetExists($name) &&
            $this->_services_protected->offsetGet($name)===true
        );
    }
300842
public function isCommandEnabled($name)
    {
        if (!empty(self::$config['application']['disabled_commands'])
            && in_array($name, self::$config['application']['disabled_commands'])) {
            return false;
        }
        if (!empty(self::$config['application']['experimental_commands'])
            && in_array($name, self::$config['application']['experimental_commands'])) {
            return !empty(self::$config['experimental']['all_experiments'])
                || (
                    !empty(self::$config['experimental']['enable_commands'])
                    && in_array($name, self::$config['experimental']['enable_commands'])
                );
        }

        return true;
    }
1213534
public function hasMethod($name)
    {
        return method_exists($this, $name)
            || (isset($this->_hookTrait) && $this->hookHasCallbacks('method-'.$name))
            || $this->hasGlobalMethod($name);
    }
1091926
public function __isset($name)
    {
        if (!in_array($name, $this->allowedFields)) {
            throw new \InvalidArgumentException(
                "The field '$name' is not allowed for this entity."
            );
        }
        
        return isset($this->values[$name]);
    }