Check whether a variable name is a magic variable.

@param string $name

@return bool
499180
public static function isSpecialVariableName($name)
    {
        return \in_array($name, self::$specialNames) || \in_array($name, self::$commandScopeNames);
    }
153935
public function has(string $name) : bool
    {
        if (Arr::keyExists($this->registry, $name)) {
            return true;
        } else {
            return false;
        }
    }
582162
public function isSettingSet( string $name ): bool
	{
		return isset($this->settings[$name]) && !is_null($this->settings[$name]);
	}
1255718
private function _checkVariableNameLength($name) {
		if ($this->_isActive('localScopeVariableLength')) {

			// we remove the $ sign
			$name = substr($name, 1);

			// we check for exceptions to the rule
			if ($this->_config->isException('localScopeVariableLength', $name)) {
				return;
			}

			$length = strlen($name);
			$min = $this->_config->getTestProperty('localScopeVariableLength', 'minLength');
			$max = $this->_config->getTestProperty('localScopeVariableLength', 'maxLength');

			// we check the min length
			if (!empty($min) && ($length < $min)) {
				$msg = $this->_getMessage('VARIABLE_NAMING_LENGTH_SHORT', $name);
				$this->_writeError('localScopeVariableLength', $msg);
			}

			// we check the max length
			if (!empty($max) && ($length > $max)) {
				$msg = $this->_getMessage('VARIABLE_NAMING_LENGTH_LONG', $name);
				$this->_writeError('localScopeVariableLength', $msg);
			}
		}
	}
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;
    }
1226521
public function __isset( $name ) {
		$func = "get_{$name}";
		if ( method_exists( $this, $func ) ) {
			return true;
		}
		$func = "is_{$name}";
		if ( method_exists( $this, $func ) ) {
			return true;
		}

		return isset( $GLOBALS[ $name ] );
	}
159442
final protected function isElementNameValid(string $name): bool
    {
        return $name &&
            false === strpos($name, ' ') &&
            preg_match('#^[\pL_][\pL0-9._:-]*$#ui', $name);
    }
893392
public function hasAttr(string $name): bool {
        return (bool)$this->collection()->reduce(function($carry, $node) use ($name) {
            if ($node->hasAttribute($name)) {
                return true;
            }

            return $carry;
        }, false);
    }
1224105
public function __isset($name)
    {
        return array_key_exists($name, $this->_data) || array_key_exists($name, self::$_globalData);
    }
571342
public function isUsing($name)
    {
        if (isset($this->using)) {
            if ($this->using->getName() == $name) {
                return true;
            }
        }

        return false;
    }
488777
public function isElementNillable($name)
    {
        foreach ($this->element->getElementsByTagName('element') as $element) {
            if ($element->getAttribute('name') == $name && $element->getAttribute('nillable') == true) {
                return true;
            }
        }
        return false;
    }
275365
public function has(string $name): bool
    {
        return isset($this->handlers[$name]) && count($this->handlers[$name]) > 0;
    }
115413
public function __isset($name)
    {
        return isset($this->properties[$name]) && !empty($this->properties[$name]);
    }
1020103
function isVariableModified( $blockName, $varName )
    {
        return ( isset( $this->ModifiedBlockValues[$blockName][$varName] ) and
                 $this->ModifiedBlockValues[$blockName][$varName] );
    }
561160
public function isManagedResource($name)
    {
        $needle = $this->getControllerId();
        $length = strlen($needle);
        return (substr($name, 0, $length) === $needle);
    }
961948
public function __isset($name)
    {
        $normalized = lcfirst($name);
        $property = "_{$normalized}";
        if (property_exists($this, $property)) {
            return true;
        }
        return false;
    }
973373
protected function variable(&$name)
    {
        $s = $this->seek();
        if ($this->literal($this->lessc->vPrefix, false) &&
            ($this->variable($sub) || $this->keyword($name))) {
            if (!empty($sub)) {
                $name = array('variable', $sub);
            } else {
                $name = $this->lessc->vPrefix.$name;
            }

            return true;
        }

        $name = null;
        $this->seek($s);

        return false;
    }