P6GrammarByAugustus

grammar Gus::Test
{
	rule TOP
	{
		<expression> | <assignment> | <term>
	}

	rule expression
	{
		(['(' <expression> ')'] | <term>) <op> (['('<expression>')'] | <term>)
	}

	rule assignment
	{
		<var> '=' [<expression> | <term>]
	}

	rule term
	{
		<number> | <var>
	}

	token number
	{
		\d+['.'\d+]?
	}

	token var
	{
		\w+
	}
	
	token op
	{
		'+' | '-' | '*' | '/'
	}
}