Top-Down Parsing/Exercise 3 - Revision history

Root at 14:40, 6 April 2015

2015-04-06T14:40:50Z

2015-03-27T15:01:30Z

FIRST & FOLLOW sets

2015-03-27T14:55:49Z

Elimination of Mutual Recursion: Expanding F in G

@@ Line 126: / Line 126: @@
   F' -> a c F' e F" | b F" e F" | d G' b
   F" -> c G' b | (eps)
 [[category:Compilers]]
 [[category:Teaching]]

2015-03-27T14:04:33Z

ELimination of Mutual Recursion: Expanding F in G

← Older revision		Revision as of 14:04, 27 March 2015
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	F" -> d b F' \| a c F" e F' \| b F' e F'		F" -> d b F' \| a c F" e F' \| b F' e F'
	-->		-->
	== ~~ELimination~~ of Mutual Recursion: Expanding F in G ==		=== Elimination of Mutual Recursion: Expanding F in G ===

	Initial grammar:		Initial grammar:

2015-03-27T14:04:16Z

Solution

← Older revision		Revision as of 14:04, 27 March 2015
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	Something to keep in mind at all times: '''never eliminate the rules corresponding to the initial symbol'''		Something to keep in mind at all times: '''never eliminate the rules corresponding to the initial symbol'''
			<!--
	There are two ways of handling the mutual recursion: either expanding F in G or G in F.		There are two ways of handling the mutual recursion: either expanding F in G or G in F.

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	F' -> c b F' \| (eps)		F' -> c b F' \| (eps)
	F" -> d b F' \| a c F" e F' \| b F' e F'		F" -> d b F' \| a c F" e F' \| b F' e F'
			-->
	== Expanding F in G ==		== ELimination of Mutual Recursion: Expanding F in G ==

	Initial grammar:		Initial grammar:

2011-03-21T10:15:05Z

Expanding F in G

2010-04-16T19:19:48Z

Solution

← Older revision		Revision as of 19:19, 16 April 2010
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	Something to keep in mind at all times: '''never eliminate the rules corresponding to the initial symbol'''		Something to keep in mind at all times: '''never eliminate the rules corresponding to the initial symbol'''

	There are two ways of handling the mutual recursion: either ~~expand~~ F in G or G in F.		There are two ways of handling the mutual recursion: either expanding F in G or G in F.

	== Expanding G in F ==		== Expanding G in F ==

2010-04-16T19:16:48Z

Expanding F in G

← Older revision		Revision as of 19:16, 16 April 2010
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	F" -> c G' b \| (eps)		F" -> c G' b \| (eps)

	Factoring F' prefixes:		Factoring F' prefixes, we get to the final version:

	G -> a c G" \| b c G' \| (eps)		G -> a c G" \| b c G' \| (eps)

2010-04-16T19:15:36Z

← Older revision		Revision as of 19:15, 16 April 2010
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			{{TOCright}}
	= Problem =		= Problem =

	Consider the following grammar, where '''<tt>F</tt>''' is the initial symbol and '''<tt>{a,b,c,d,e}</tt>''' is the set of terminal symbols:		Consider the following grammar, where '''<tt>G</tt>''' is the initial symbol and '''<tt>{a,b,c,d,e}</tt>''' is the set of terminal symbols:

	O -> a		O -> a

2010-04-16T19:07:13Z

Solution

@@ Line 69: / Line 69: @@
   F' -> c b F' | (eps)
   F" -> d b F' | a c F" e F' | b F' e F'
 [[category:Compilers]]
 [[category:Teaching]]