(a) Develop a regular expression and/or a Cocol token definition that describes identifiers of the sort used in many programming languages, subject to the restriction that underscores may not appear at the start or end of an identifier. but may appear in the interior of an identifier.
(b) Develop a regular expression and/or a Cocol description that describes comments of the form allowed in the C family of languages.
Hint: Here are some examples of strings that might be valid comments. One of them, however, cannot be a comment. Which is it? Can your Regular Expression accommodate the valid ones?
(1) /* comment */
(2) /* multiply a * b */
(3) /* divide a / b */
(4) /* ***** */
(5) /*********/
(6) /* ** /* // */
(7) /* // */ ** */
(8) /*a*b*/
(9) /* **a/b* ** */
(c) Develop a Cocol grammar to describe a list of names of some well loved (well, well respected) folk who have titles, first names and/or initials, surnames, and (usually) qualifications - for example
Professor P.D. Terry, MSc, PhD .
George Clifford Wells, BSc(Hons), MSc, PhD .
C. Hubert H. Parry, BMus.
Greg G. Foster, PhD .
Dave A. Sewry, PhD .
Dr Karen Lee Bradshaw, MSc, PhD .
Caro Watkins, BSc .
Professor Richard J. Foss, PhD.
Your Name One Day, BSc(InfSys), PhD .
Mx Mic Halse .
Madonna .
Dr Mabizela .
(d) The contents of a very useful textbook (if you can find a copy) begins as follows:
All you need to know to be able to pass your compiler examination.
by
Pat Terry.
Chapter 1 Bribery is unlikely to succeed.
Chapter 2 Understand the phases of compilation.
2.1 Lexical and syntactic analysis are easily confused
2.2 Constraint analysis involves the concept of type
2.3 Code generation for the PVM is a breeze
Chapter 3 Get clued up on grammars.
3.1 Terminals
3.2 Sentences and sentential forms
3.3 Regular Expressions
3.4 Productions
3.5 EBNF and Cocol
3.6 Ambiguity is bad news
and so on. Develop a Cocol grammar that describes the contents. Assume that the words in the contents are all fairly simple, but notice that full stops (periods) appear in significant places. Since this is a long course, you should be able to handle more than three chapters, and some of might them have many sub- sections.