Parse Trees

















Construct a parse tree for the string using the grammar.

	(x * (1 + y))

	E -> (E + E)
	E -> (E * E)
	E -> 1
	E -> x
	E -> y


















Classwork

You may work with a partner.

Construct a parse tree for the string using the grammar.

	x * 1 + y

	E -> E + T | T
	T -> T * F | F
	F -> 1 | x | y


















Classwork

You may work with a partner.

Construct a parse tree for the string using the grammar.

	a monkey talks wildly

	sentence -> noun-phrase verb-phrase
	noun-phrase -> article noun
	verb-phrase -> verb adverb
	article -> a
	article -> the
	noun -> tree
	noun -> monkey
	verb -> eats
	verb -> talks
	adverb -> wildly
	adverb -> loudly


















What's the label of the Root of a parse tree?


What are the labels of the Leaves of a parse tree?


What are the labels of the Interior Nodes of a parse tree?


How are production applications shown in the parse tree?


Is any node in the tree labelled with more than one grammar symbol?

















What's a Top-down Parse?

	begin with the start nonterminal
	at each step, choose a production to rewrite a nonterminal
	stop when no nonterminals remain


What's a Bottom-up Parse?

	begin with the input string
	at each step, reduce a substring to a nonterminal
	stop when only the start nonterminal remains