CS 541 Lecture -*- Outline -*-

* abstract syntax

** motivation
	ambiguity, and exactly how parse trees are generated are important,
	but NOT during early design

	also, for semantics, details of syntax aren't important
		as want to give meaning to PARSE TREES, not strings

** definition
	not a hard an fast thing

	abstract syntax only concerned with hierarchical relationships,
		not with terminals and bracketing

	specifies set of abstract syntax trees

	so can often use ambiguous grammars (e.g., for expressions)

	example, LISP syntax is abstract syntax (usually)