CMPT 120 Chapter Notes - Chapter 1: Formal Language, Chemical Formula, Parsing

• School: Simon Fraser University
• Department: Computing Science
• Course: CMPT 120
• Professor: Liaqat Ali

Document Summary

Formal languages tend to have strict syntax rules that govern the structure of statements. For example, in mathematics the statement 3 + 3 = 6 has correct syntax, but 3+ = 3 does not. In chemistry h2o is a syntactically correct formula, but 2zz is not. Syntax rules come in two flavors, pertaining to tokens and structure. Tokens are the basic elements of the language, such as words, numbers, and chemical elements. One of the problems with 3+ = 3 is that $ is not a legal token in mathematics (at least as far as i know). Similarly, 2zz is not legal because there is no element with the abbreviation zz. The second type of syntax rule pertains to the way tokens are combined. The equation 3+ = 3 is illegal because even though + and = are legal tokens, you can"t have one right after the other.