Unformatted text preview: sometimes called syntactic categories. We will use the convention that nonterminals and sets have names that are
capitalized, but we will use lower-case names when referring to their elements in prose. This is simpler than it sounds. For example, Expression is a
nonterminal, but we will write e Expression or “e is an expression.” ¢ Another common convention, called Backus-Naur Form or BNF, is to surround the word with angle brackets, e.g. expression .
¡ Terminal Symbols. These are the characters in the external representation,
in this case , , and . We typically write these using a typewriter font,
4 ¤ Productions. The rules are called productions. Each production has a lefthand side, which is a nonterminal symbol, and a right-hand side, which
consists of terminal and nonterminal symbols. The left- and right-hand sides
are usually separated by the symbol :: , read is or can be. The right-hand
side speciﬁes a method for constructing members of the syntactic category
in terms of other syntactic categori...
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- Fall '09
- Data Structures, eopl, ¡§ £¡, Dr. Wand