Exercises for Section 3.1

3.1.1

Divide the following C++ program:

float limitedSquare(x){float x;
  /* returns x-squared, nut never more than 100 */
  return (x <= -10.0 || x >= 10.0) ? 100 : x*x;
}

into appropriate lexemes, using the discussion of Section 3.1.2 as a guide. Which lexemes should get associated lexical values? What should those values be?

Answer

<float> <id, limitedSquaare> <(> <id, x> <)> <{>
  <float> <id, x>
  <return> <(> <id, x> <op,"<="> <num, -10.0> <op, "||"> <id, x> <op, ">="> <num, 10.0> <)> <op, "?"> <num, 100> <op, ":"> <id, x> <op, "*"> <id, x>
<}>

3.1.2

Tagged languages like HTML or XML are different from conventional programming languages in that the punctuation (tags) are either very numerous (as in HTML) or a user-definable set (as in XML). Further, tags can often have parameters. Suggest how to divide the following HTML document:

Here is a photo of <b>my house</b>;
<p><img src="house.gif"/><br/>
see <a href="morePix.html">More Picture</a> if you
liked that one.</p>

into appropriate lexemes. Which lexemes should get associated lexical values, and what should those values be?

Answer

<text, "Here is a photo of"> <nodestart, b> <text, "my house"> <nodeend, b>
<nodestart, p> <selfendnode, img> <selfendnode, br>
<text, "see"> <nodestart, a> <text, "More Picture"> <nodeend, a>
<text, "if you liked that one."> <nodeend, p>