src/Command.php
public function syntax(string $syntax = null)
    {
        if (null === $syntax)
            return $this->syntax;

        $this->syntax = S::syntax()->parse("{{$syntax}| }");
        return $this;
    }
public function syntax(string $syntax = null)
    {
        if (null === $syntax)
            return $this->syntax;

        $this->syntax = S::syntax()->parse("{{$syntax}| }");
        return $this;
    }
public function syntax ( string $ syntax = null ) { if ( null === $ syntax ) return $ this -> syntax ; $ this -> syntax = S :: syntax ( ) -> parse ( "{{$syntax}| }" ) ; return $ this ; }
syntax getter and setter.

@param  string|null $syntax
@return Syntax|self
syntax getter and setter .