Day15 - Day 15 Version 2.0 Item#20 Brief comments on 5.1,2...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Day 15, March 18, 2008, Version 2.0 Item #20. Brief comments on §5.1,2. These sections are really too easy for you to need my lecturing on them, but I’ll provide a few background comments. In §5.1 we see that a regular grammar is a special case of a context free grammar (cfg), since in a cfg, the right hand side of production rules can be any concatenation of terminals and non-terminals —that’s what (V c T)* means in the definition. Analogously we saw that a dfa can be regarded as a special case of an ndfa in which no 8 transitions are used, and where we identify the state q i of the dfa with the state {q i } of a ndfa. In §5.2 we see what it means for a grammar to be ambiguous. (This will overlap your Programming Languages course; little harm in that.) Some students on our midterm exam defined “non-determinism” as if it meant “ambiguous” so it’s a good idea to meet the concept of ambiguity just by way of contrast. A grammar is ambiguous if it has at least one ambiguous sentence. A sentence is ambiguous if it has two
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Ask a homework question - tutors are online