Launching Apart from certain small craft built on inland waterways, which are launched sideways, the great majority of ships are launched stern first from the building berth. Standing structurc called ways, constructed of concrete and wooden blocks, spaced about one-third of the vessel's
One parse tree only a The role of the grammar a distinguish between syntactically legal and illegal programs a But that's not enough: it must also define a parse tree a the parse tree conveys the meaning of the program What if a string can be parsed with multiple parse trees? a we say the grammar is ambiguous a must fix the grammar(the problem is not in the parser) a Note: often a string can be derived in more than one way D ie, with more than one derivation sequence o this does not mean the grammar is ambiguous